The fatty acid composition of serum phospholipids in adolescents is associated with body composition in early adulthoods: an eight-year follow-up study

The fatty acid composition is associated with obesity. Omega 3 polyunsaturated fatty acid (PUFA) could have a beneficial role in the prevention and treatment of many disorders, including cardiometabolic diseases. A cohort of 84 men and 131 women were examined in adolescence and after 8 years. Body weight (BW) and fat mass (FM) were measured. The composition of fatty acids (FAs) of serum phospholipids was assessed using gas chromatography. Statistics: PLS method. Aim: to determine the relationships between FAs in adolescence and FM (explanatory variable 1, EV1) and BW (explanatory variable 2, EV2) in adulthood. In the predictive models, a cluster of FAs in boys explained 47.2 % of EV1 and a cluster of 6 FAs in girls explained 32.3 % of EV1 measured in adulthood. FAs measured in adolescents explained 23.7 % of EV2 in early adults regardless of gender. A significant negative association was found between 18:1n-9c and EV1 in males and EV2 in both genders. We found a significant negative association between 18:2n-6 and 20:0 and both EV1 and EV2. In all analyses, we found a significant negative association of 20:1n-9 and 18:3n-3 with EV1-2 in both genders. A significant positive association was found in 20:3n-6 with EV1 and EV2 in males. 20:4n-6 was positively associated with EV1 in females and EV2 in both genders. A positive association between FM and very long chain n- 6 PUFAs was also observed. It is concluded that serum MUFAs and essential PUFAs in adolescence are associated with lower BW and FM in adulthood.

The assessment of plasma fatty acid profiles in newly diagnosed treatment-naive paediatric Crohn's disease

Fatty acid (FA) profiles as potentially relevant components of Crohn's disease (CD) have been insufficiently analysed. We sought to explore the plasma profiles of n-3 and n-6 polyunsa-turated fatty acids (PUFAs) in newly diagnosed untreated active CD. We included 26 consecutive CD pediatric patients (<19 years) and 14 healthy controls (HCs). Disease characteristics, including inflammatory markers, dietary histories, and the Pediatric Crohn's Disease Activity Index (PCDAI), were obtained. The profiles of plasma FAs in plasma lipid classes were analysed by gas chromatography with FID detection of methyl esters. The erythrocyte sedimentation rate, C-reactive protein level and fecal calprotectin level (all p<0.001) were significantly higher in CD patients than in HCs. Most changes were observed in plasma phospholipids (PLs), such as a higher content of n-3 and changes in n-6 long-chain PUFAs in the CD group. The CD group had a lower ratio of n-6/n-3 PUFAs in PLs (p<0.001) and triacylglycerols (TAGs) (p<0.01). Correlations of the FA content in plasma PLs with disease activity scores of CD were also observed, which were positive for the sum of monounsaturated fatty acids (MUFAs) as well as oleic acid (18:1n-9) (both p<0.05). The metabolism of PUFAs is significantly altered even in treatment-naive newly diagnosed active pediatric CD, and the content of major FAs in PLs correlates with disease activity and inflammatory markers, thus probably contributing to the still unclear early disease pathogenesis.

Polymorphisms rs2167444 and rs508384 in the SCD1 Gene Are Linked with High ApoB-48 Levels and Adverse Profile of Cardiometabolic Risk Factors

Elevated plasma concentration of apolipoprotein B-48 (apoB-48) is an independent risk factor of cardiovascular disease. Stearoyl-CoA desaturase-1 (SCD1) is a rate-limiting lipogenic enzyme and a key regulator of fuel metabolism. The aim of this study was to analyse associations between clinical, biochemical, and genetic factors and different apoB-48 levels in subjects at increased cardiometabolic risk. We examined 220 subjects exhibiting at least one metabolic syndrome (MetS) component. In conjunction with basic clinical, anthropometric and laboratory measurements, we analysed various polymorphisms of stearoyl-CoA desaturase-1 (SCD1). Subjects were divided into two groups according to the median apoB-48 level: (1) high apoB-48 (≥ 7.9 mg/l, N = 112) and (2) low apoB-48 (< 7.9 mg/l, N = 108). Neither group differed significantly in anthropometric measures. High plasma apoB-48 levels were associated with increased systolic blood pressure (+3 %; P < 0.05), MetS prevalence (59.8 vs. 32.4 %; P < 0.001), small-dense LDL frequency (46.4 vs. 20.4 %; P < 0.001), triglycerides (+97 %; P < 0.001), non-HDLcholesterol (+27 %; P < 0.001), and lower concentrations of HDL-cholesterol (-11 %; P < 0.01). This group was further characterized by a higher HOMA-IR index (+54 %; P < 0.001) and increased concentrations of conjugated dienes (+11 %; P < 0.001) and oxidatively modified LDL (+ 38 %; P < 0.05). Lower frequencies of SCD1 minor genotypes (rs2167444, rs508384, P < 0.05) were observed in subjects with elevated plasma concentrations of apoB-48. Elevated plasma concentrations of apoB-48 are associated with an adverse lipid profile, higher systolic blood pressure, insulin resistance, and oxidative stress. Lower proportions of minor SCD1 genotypes (rs2167444, rs508384) implicate the role of genetic factors in the pathogenesis of elevated levels of apoB-48.

Fatty acid composition of adipose tissue triglycerides after weight loss and weight maintenance: the DIOGENES study

Fatty acid composition of adipose tissue changes with weight loss. Palmitoleic acid as a possible marker of endogenous lipogenesis or its functions as a lipokine are under debate. Objective was to assess the predictive role of adipose triglycerides fatty acids in weight maintenance in participants of the DIOGENES dietary intervention study. After an 8-week low calorie diet (LCD) subjects with > 8 % weight loss were randomized to 5 ad libitum weight maintenance diets for 6 months: low protein (P)/low glycemic index (GI) (LP/LGI), low P/high GI (LP/HGI), high P/low GI (HP/LGI), high P/high GI (HP/HGI), and a control diet. Fatty acid composition in adipose tissue triglycerides was determined by gas chromatography in 195 subjects before the LCD (baseline), after LCD and weight maintenance. Weight change after the maintenance phase was positively correlated with baseline adipose palmitoleic (16:1n-7), myristoleic (14:1n-5) and trans-palmitoleic acid (16:1n-7t). Negative correlation was found with baseline oleic acid (18:1n-9). Lower baseline monounsaturated fatty acids (14:1n-5, 16:1n-7 and trans 16:1n-7) in adipose tissue triglycerides predict better weight maintenance. Lower oleic acid predicts lower weight decrease. These findings suggest a specific role of monounsaturated fatty acids in weight management and as weight change predictors.

Polymorphisms of genes for brain-derived neurotrophic factor, methylenetetrahydrofolate reductase, tyrosine hydroxylase, and endothelial nitric oxide synthase in depression and metabolic syndrome

The prevalence of metabolic syndrome as well as the occurrence of depressive disorder, which are both connected with increased risk of diabetes mellitus type 2 and cardiovascular diseases, is continually increasing worldwide. These disorders are interconnected at various levels; the genetic one seems to be promising. Contribution of genetic factors to the aetiopathogenesis of depressive disorder weighs within the range 40-50 %, whereas the genetic background for the manifestation of metabolic syndrome is more complicated. In this pilot study, we investigated the incidence of polymorphisms in several genes supposed to play a role in the development of both depressive disorder and metabolic syndrome such as brain-derived neurotrophic factor, methylenetetrahydrofolate reductase, tyrosine hydroxylase, and endothelial nitric oxide synthase. The entire group consisted of 42 patients with depressive disorder, 57 probands with metabolic syndrome and 41 control individuals. We found that genotype Met/Met of the Val66Met polymorphism of the brain-derived neurotrophic factor gene was positively associated with depressive disorder (P < 0.05), but we were not able to find any significant associations of both the depressive disorder and metabolic syndrome with the remaining polymorphisms studied (methylenetetrahydrofolate reductase 677CT, methylenetet rahydrofolate reductase 1298AC, endothelial nitric oxide synthase Glu298Asp, and tyrosine hydroxylase).

[Fatty acids--2. Clinical and physiological significance]

Fatty acids play multiple roles in humans and other organisms. In triglycerides they are the source of metabolic energy, in adipose tissue they serve also as temperature and mechanical isolators, in the form of phospholipids they are structural components of membranes. Fatty acids originating from the sn-2 glycerol carbon of phosphatidylcholine can influence the activity of diglycerides as second messengers. Unsaturated FA with 18-20 carbon atoms are precursors of prostaglandins, leucotrienes and thromboxanes, which have a broad scale of regulatory properties and have autocrine as well as paracrine effects. Fatty acids are ligands of several nuclear receptors, which take part in the subcellular control of a number of metabolic pathways. Covalent modification of proteins by FA (acylation) enables FA incorporation into the membranes. Number of pathological stages is accompanied with changes in fatty acid composition, often expressed as decreased content of unsaturated and increased content of saturated fatty acids (e.g. dyslipidemia, malnutrition, inflammation and inherited diseases). Polyunsaturated fatty acids as dietary supplements are used in prevention and in the therapy of cardiovascular diseases and other metabolic disturbances.

[Fatty acids--1. occurrence and biological significance]

Fatty acids are monocarboxylic acids with chain-length 2-36 carbon atoms and 0-6 double bonds. Their physico-chemical properties are reflected also in the compounds, where fatty acids represent an important component (phospholipids, triglycerides), as well as in higher organized structures (plasma membranes, lipoproteins). Fatty acids are synthesized from two-carbon precursors; their degradation by beta-oxidation is accompanied by energy-release. Fatty acids are classified with respect to double bonds into saturated, monounsaturated and polyunsaturated. Simple lipids are esters of fatty acids and organic alcohols - cholesterol, glycerol and sphingosine and their derivatives. Endogenous acids can be desaturated up to Delta9 position; desaturation to other position is possible only from exogenous (essential) acids [(linoleic (n-6 series) and alpha-linolenic (n-3 series)]. Circulating lipids (in form of lipoproteins) consist of cholesterol esters and triglycerides in nonpolar core and phosphatidylcholin and sphingomyelin in the polar envelope of lipoproteins. Nonesterified fatty acids (product of lipolysis and source for lipid synthesis) are bound to plasma albumin. Membrane lipids, which ensure membrane fluidity and other functions, consist of phosphatidylcholine, phosphatidylethanolamine, sphingomyelin and some other (minor) phospholipids.

[Features of metabolic syndrome in patients with depressive disorder]

BACKGROUND

Depressive disorder is a serious illness with a high incidence, proxime accessit after anxiety disorders among the psychiatric diseases. It is accompanied by an increased risk of development of type 2 diabetes mellitus, cardiovascular disease, and by increased all-cause mortality. Recently published data have suggested that factors connected with the insulin resistance are at the background of this association.

METHODS AND RESULTS

In this pilot study we have investigated parameters of lipid metabolism and glucose homeostasis in consecutively admitted patients suffering from depressive disorder (DD) (group of 42 people), in 57 patients with the metabolic syndrome (MetS) and in a control group of 49 apparently healthy persons (CON). Depressive patients did not differ from the control group by age or body mass index (BMI) value, but they had statistically significantly higher concentrations of serum insulin, C-peptide, glucose, triglycerides (TG), conjugated dienes in LDL particles (CD-LDL), higher value of microalbuminuria and of insulin resistance (HOMA-IR) index. They simultaneously had significantly lower value of the insulin sensitivity (QUICKI) index. In comparison with the MetS group the depressive patients were characterized by significantly lower both systolic and diastolic blood pressure, BMI , serum TG, apolipoprotein B, uric acid, C-peptide and by higher concentrations of apolipoprotein A-I and HDL-cholesterol. On the contrary, we have not found statistically significant differences between the DD and MetS groups in the concentrations of serum insulin, glucose, HOMA and QUICKI indices, in CD-LDL and MAU.

CONCLUSIONS

In this pilot study, we have found in patients with depressive disorder certain features of metabolic syndrome, especially insulin resistance and oxidative stress.

[Metabolic syndrome and depression--clinical relations]

The occurrence of both obesity and type 2 diabetes mellitus is rapidly increasing; according to WHO data, this can be considered as a worldwide epidemic. The obesity is one of the components of metabolic syndrome, the cluster of several risk factors of atherosclerosis such as dyslipidemia, hypertension, impaired glucose homeostasis, pro-thrombotic state and subclinical inflammation. The importance of the metabolic syndrome is confirmed by findings of the several times increased risk of both the type 2 diabetes mellitus and cardiovascular disease. Similarly, as in the case of obesity and diabetes, the incidence and prevalence of depressive disorder are still increasing and depressive disorder belongs to the most important causes of disability. The interrelations between depressive disorder and diabetes are known for a long time. Diabetics very often suffer from depression and vice versa, the depressive disorder is a significant risk factor of type 2 diabetes mellitus development and worsens the survival of diabetics. Those relationships have been recently intensively studied. Our paper reviews genetic, nutritional, metabolic and hormonal factors, contributing to the above mentioned syndrome.

Change in Fatty Acid Composition of Serum Lipids in Obese Females after Short-Term Weight Reducing Regimen with the Addition of n-3 Long Chain Polyunsaturated Fatty Acids In Comparison To Controls

Short-term weight-reducing regimens were shown to influence fatty acid composition of serum lipids unfavorably. Adding long chain n-3 polyunsaturated fatty acids (n-3 LC PUFA) to a low-calorie diet (LCD) could avoid these changes. The aim of this study was to examine the effect of a short-term in-patient weight-reducing regimen including LCD with yogurt enriched by low doses of n-3 PUFA (n-3 LCD). The enriched yogurt contained 790 mg of fish oil, predominantly eicosapentaenoic (20:5n-3; EPA) and docosahexaenoic (22:6n-3; DHA). Forty obese women were randomly assigned to the group consuming LCD and joghurt either with or without n-3 enrichment. Following the 3-week diet in the n-3 LCD group a significantly higher increase in the proportion of n-3 LC PUFA (sum of n-3 FA, EPA and DHA) in serum lipids was confirmed. In phospholipids (PL) a significant difference in the sum of n-6 fatty acids was found, a decrease in the n-3 LCD group and an increase in LCD group. Significantly higher increase in the PL palmitate (16:0) was shown in the LCD group. The results suggest that low doses of n-3 fatty acid enrichment can help to avoid unfavorable changes in fatty acid composition in serum lipids after a short-term weight-reducing regimen.

[Conjugated linoleic acid--the dietary supplement in the prevention of cardiovascular diseases]

Conjugated linoleic acid is an integral term for the mixture of positional and geometrical isomers of the octadecadienoic acids, whose two double-bonds are separated with one single-bond. The most common isomers are cis-9, trans-11, and trans-10, cis-12. Conjugated linoleic acid is present in the food namely in the red meat and dairy products which the contemporary dietary recommendations tend to limit. Those limitations should be compensated with dietary supplements. Experimental studies have shown the positive effects of the conjugated linoleic acid in the regulation of the body weight, in the reduction of risk factors of cardiovascular diseases, for improvement of immunity and in the reduction of risks of the development of some carcinomas. Those studies have also considered different effects of individual isomers. Stimulating results of experimental studies represent the basis of the research in human medicine, where the results are not so unequivocal. Studies are difficult to compare owing to the different arrangement (number of persons, daily dose, length of administration). Positive effects on the adiposity and proportion of the visceral fat was observed after the long-term administration, however, mechanism of the effect has not been explained yet. It can be due to the inhibition of lipoprotein lipase, rise of carnitine-palmitoyl transferase activity, induction of adipocyte apoptosis, modulation of PPARgamma effects. For the explanation some new long-term studies with defined clinics will be necessary. Present view on the indication of the conjugated linoleic acid administration from the point of complex modulation of risks of the development of cardiovascular and metabolic diseases is inconsistent.

[Composition of the nonesterified fatty acids and lipid peroxidation in metabolic syndrome]

BACKGROUND

Composition of the nonesterified fatty acids in plasma in metabolic syndrome patients and in other syndromes of insulin resistance is altered. Fatty acid profile in plasma is related to the composition of dietary fat and to the metabolic changes of fatty acids, e.g. to de novo lipogenesis, beta-oxidation and conversion accompanying the oxidative stress. The aim of the work was to study the fatty acid composition in the major plasma lipid classes in relation to the insulin resistance, to some polymorphisms of candidate genes with activity related to insulin resistance, and to the lipoprotein composition and parameters of lipid peroxidation.

METHODS AND RESULTS

95 patients with metabolic syndrome (56 M/39 F) and 195 healthy persons (99 M/96 F) were included into the cohort. Basic clinical data, parameters of glucose homeostasis, lipid concentration in plasma and conjugated diens in LDL were determined. Fatty acids were detected by capillary gas chromatography. Polymorphisms of apolipoprotein E, intestinal isoforms of fatty acid binding protein (Ala54Thr) and y-2 isoforms of peroxisomal activated receptor (Alal2Pro) were analyzed using combination of polymerase chain reaction methods and by the detection of polymorphisms of the restriction fragment length. Persons with metabolic syndrome had higher concentrations of CRP and conjugated diens in LDL. In all lipid classes we proved a decreased concentration of n-6 polyunsaturated fatty acids and an increase of unsaturated fatty acids. From all the acids, the only significant was the decrease of linolic acid concentration and the increase of palmitic and palmitoyl acids. Results showed an increase of delta 9 palmitic acid desaturase activity, delta 6 linolic acid desaturase and elongase activity. Concentration of conjugated diens in LDL inversely correlated with linolic acid. Clinical or laboratory parameters and homozygotic combination of polymorphism studied were not mutually related.

CONCLUSIONS

Changes in the profile of fatty acids during the metabolic syndrome results from the elevated lipogenesis and from the higher level of oxidative stress.

[Effect of hypolipidemic treatment on the composition of bile and the risk or cholesterol gallstone disease]

Obesity, diabetes mellitus type 2 and dyslipidemia, characterized by hypertriglyceridemia and low HDL-cholesterol levels, are risk factors for cholesterol gallstone disease. The common denominator of above-mentioned states is insulin resistance. Hypolipidemic treatment significantly influences not only the biliary lipid composition, but also other etiopathogenetic mechanisms of the disease. Three principal defects are involved in gallstone formation - cholesterol supersaturation, accelerated nucleation, and gallbladder dysmotility. The degree of cholesterol saturation in gallbladder bile is the most important predictor of cholesterol crystal formation. Cholesterol, lecithin and bile acids are the major components in bile. According to the molar ratios of the three main components, simple or mixed micelles, unstable unilamellar or multilamellar vesicles are formed in the bile. The cholesterol supersaturation of the gallbladder bile and cholesterol crystal formation from the unstable multilamellar vesicles initiates the onset of cholesterol cholelithiasis. The pool of unesterified cholesterol is the source for VLDL synthesis; together with HDL-cholesterol, it is also the source for cholesterol secretion into the bile. The main metabolic products of cholesterol degradation are bile acids, which are synthesized predominantly from LDL-cholesterol. The rate of the production of primary bile acids is principally regulated by cholesterol 7alpha-hydroxylase (CYP7A 1). The treatment of dyslipidemia with niacin and resins does not influence the saturation of bile with cholesterol or the incidence of cholelithiasis. The effects of ezetimibe in human patients with the respect of cholesterol cholelithiasis have not been published. The fibrate treatment is associated with increased cholesterol saturation of bile due to inhibition of CYP7A1 activity, enhanced flux of cholesterol via HDL and increased secretion of cholesterol into bile. The clinical studies describe cholesterol supersaturation in bile and increased frequency of cholelithiasis as well. The administration of pravastatin and simvastatin led to reduced cholesterol saturation indexes. The patients with endogenous hypertriglyceridemia and low HDL-cholesterol being administered with polyunsaturated fatty acids of n-3 family had decreased cholesterol concentration in bile. Other authors described beneficial effect of fish oil on the biliary cholesterol nucleation time, improvement of gallbladder sensitivity to cholecystokinin and the prevention of cholesterol gallstone formations caused by rapid weight loss.

[Factors modulating parameters of cholesterol homeostasis in the metabolic syndrome]

BACKGROUND

Newly described component of the metabolic syndrome is the elevated synthesis of cholesterol accompanied with its decreased intestinal absorption. The aim of our study was to ascertain the incidence of genotypes and alleles of several candidate genes, which modulate insulin resistance and metabolism of lipids and to find their role in lipid, lipoprotein and cholesterol homeostasis. The concentrations of cholesterol precursors (lathosterol, desmosterol, respectively their rations to cholesterol) are related to the synthesis of cholesterol; concentrations of fytosterols (kampesterol, sitosterol, respectively their rations to cholesterol) are related to the intestinal absorption of cholesterol.

METHODS AND RESULTS

95 patients with metabolic syndrome (56 M/39 F) and 195 healthy persons (99 M/96 F) were included into the study. Beside the basic clinical and anthropometric data, parameters of glucose homeostasis, plasma concentration of lipids, ultracentrifugation separated lipoproteins, and conjugated diens in LDL were determined. Non-cholesterol sterols were estimated by capillary gas chromatography. Polymorphisms of apolipoprotein E, intestinal isoforms of fatty acids binding protein (Ala54Thr), microsomal transfer protein (-493G/T), and gamma-2 isoforms of peroxisomal proliferator activated receptor (Ala12Pro) were analysed by combination of methods of polymerase chain reaction and by determination of polymorphism of the length of restriction fragments. After adjustation to the age, patients with metabolic syndrome had higher BMI, body fat and lean body weight (all P < 0.001), waist circumference, systolic and diastolic blood pressure (all P < 0.01). At the same time they had higher levels of glucose, insulin (P < 0.001), C-peptide, CRP (P < 0.05), uric acid, conjugated diens in LDL and HOMA insulin resistance index (P < 0.001). After adjustation to the age, higher concentration of triglycerides (P < 0.001), apo B (P < 0.01), cholesterol and triglycerides in VLDL (both P < 0.001), triglycerides in LDL (P < 0.01) were found. Incidence of alleles and genotypes of studied polymorphisms did not differ in both groups. Cholesterol synthesis is modulated by the presence of metabolic syndrome and by sex; cholesterol resorption is modulated only by the presence of metabolic syndrome.

CONCLUSIONS

In patients with metabolic syndrome we found higher synthesis and lower intestinal absorption of cholesterol. We did not confirm relation between alleles of studied polymorphisms and clinical and anthropometric parameters, neither relation of these alleles to lipid or lipoprotein levels, oxidation stress, inflammation, or parameters of synthesis and absorption of cholesterol.

[Phytosterols as a functional food]

Many dietary recommendations which try to lower the concentration of total, respectively LDL cholesterol, force us to look back to vegetable-based diet. The plants synthesize many compounds similar to cholesterol, called phytosterols and phytostanols, and these sterols are consumed in average Western diet in amounts ranging from 200 to 500 mg/day. Phytosterols and phytostanols share the mechanisms of absorption with cholesterol molecule and influence the cholesterol metabolism inside the enterocytes. Both types of phytoanalogs of cholesterol were proven to be potent cholesterol-reducing agents; their daily intake about 2 g/day reduces the LDL-cholesterol by 15%. The underlying mechanisms involve the prevention of cholesterol absorption from the gut lumen and slower esterification rate of phytosterols (phytostanols) inside the enterocytes. In contrary to phytostanols, phytosterols are absorbed with yet-to-be-considered efficiency, appearing in plasma with concentrations reaching as much as 1% that of total cholesterol. The hypocholesterolemic effect of phytosterols (phytostanols) can be further supported with the combination of dietary (n-3 polyunsaturated fatty acids, fibre) regimen as well as pharmacological intervention (statins). To conclude, plant sterols represent safe dietary approach to lowering of plasma total cholesterol with the attention paid to the intake of lipid soluble vitamins.

[Oxidation stress, insulin resistance and endothelial dysfunction during the treatment of hyperlipidaemia]

BACKGROUND

Hyperlipidaemia represents one of the major risk factors of the type 2 diabetes mellitus (DM2). In the pathogenesis of insulin resistance (IR) development glucose homeostasis impairment and their progression into DM2, oxidative stress and endothelial dysfunction (ED) may play an important role. Recent papers indicate the possibility to prevent the development of DM2 by HLP treatment, which is characterised by increased oxidation stress and ED.

METHODS AND RESULTS

For the period of twelve months 46 patients with primary HLP (group S) (LDL-C > 4.1 mmol/l a TG < 3.5 mmol/l), were treated with atorvastatine 20 mg or simvastatine 40 mg. Patients with LDL-C > 4.1 mmol/l along with TG > 3.5 mmol/l were randomly divided into two groups. The SF group was treated with a combination of statin + 200 mg micronized fenofibrate each day, and group SR received together with statin a compound containing n-3 polyene fatty acids (PUFA n-3) in the daily dose of 3.6 g. After one year lasting therapy we found beside the positively influenced concentration of atherogenic lipids and lipoproteins in the group S and SF a significantly reduced concentration of conjugated dienes (CD) in LDL ( -21, resp. 16%, both P < 0.05); the test of KD kinetics in LDL in the group S has marginal increase of the lag phase (P = 0.06) and in the groups S and SR also a significant improvement of ED (increase by the flow of mediated vasodilation, FMD) by 20%, resp. by 18% (both P < 0.05) and in the SR group a significant decrease of microalbuminuria. We did not proved significant concentrations of insulin, C-peptide or indexes showing the degree of IR (HOMA and QUICKI) CONCLUSIONS: Long-lasting hypolipidemic treatment positively affected in our study the oxidative stress and ED, however, it did not resulted in changes of IR.

[Changes in serum and adipose tissue fatty acid composition after low calorie diet with respect to dietary fat content in obese]

BACKGROUND

Recently, a new attention has been paid to beneficial effects of high-fat diet on the body weight reduction and metabolic profile in obese subjects. In this study we compared the effects of two hypocaloric diets with different proportion of fat on fatty acid composition (FA) in blood and adipose tissue (AT).

METHODS AND RESULTS

Forty-four obese subjects were submitted to 10 weeks' low-calorie diet. Subjects were randomized into low-fat diet (LFD) (20-25% of energy content) and high-fat diet groups (HFD) (40-45%). Before and at the end of the intervention, samples of blood and subcutaneous AT were taken for the analysis of fatty acid composition. The diet-induced body weight and fat mass reduction were not different between the two diets. Plasma triacylglycerols (TAG) were reduced during HFD only. Both diets reduced proportion of n-3 polyunsaturated fatty acids in AT and of saturated fatty acid in blood TAG, with no difference between the diets. HFD induced a higher increase of monounsaturated fatty acids in blood TAG. No other diet-induced changes were found in proportion of major classes of fatty acids. In respect to individual fatty acids, the diets induced a number of changes in AT and blood, the changes, however, not being different between the diets.

CONCLUSION

Hypocaloric diets induce a number of changes in fatty acid composition in blood and adipose tissue, with little differences in respect to the proportion of fat in the diet. The results suggest the diet-induced changes in fatty acid composition are controlled by the calorie deficit of the diet and the proportion of dietary fat plays a minor role.

[Nicotinic acid: an unjustly neglected remedy]

In human organism, the administration of nicotinic acid (niacin) leads to two types of effects. Within the physiological range (approximately = 20 mg/day), niacin has a vitamin-like role as pellagra preventing factor. The pharmacological dosage (approximately 0,5-4,5 g/day) substantially influences the plasma lipid and lipoprotein concentrations: decreases VLDL and LDL concentrations, changes the profile of LDL subfractions towards the larger particles as well as particles with lower density; it also profoundly increases the concentration of HDL-C in consequence of elevated concentration of HDL2 subfraction. Niacin as the only hypolipidemic drug reduces the lipoprotein(a) concentration. The hypolipidemic mechanism of niacin is different from that of other hypolipidemic drugs. On the basis of clinically controlled trials (both interventional epidemiological and angiographical), which satisfy the criteria of evidence-based medicine, it is possible to conclude that niacin falls unambiguously into the class of hypolipidemic drugs with proven beneficial effect not only on cardiovascular mortality and morbidity, but also on total mortality. Therefore, niacin should have an indisputable role in the pharmacological control of dyslipidemias. With the respect of basic mechanism (inhibition of the lipolysis of adipose tissue) with subsequent decrease in the concentration of free fatty acids and their flux to liver, niacin fulfils the criteria for pathogenetic treatment of atherogenic dyslipidemia in metabolic syndrome. The prerequisite condition for the niacin treatment is the respect for serious adverse effects and possible health hazards of administration (skin flush, hepatotoxicity and deterioration of glucose homeostasis). Recently discovered extrahypolipidemic effects of niacin (antioxidative activity, facilitation of reverse cholesterol transport, activation of PPAR-gamma, antithrombotic effects) and the introduction of drug forms with sustained (extended resp.) release of active compound (that minimizes the adverse effects and administration hazards) form together the basis for firm statement that the derivatives of nicotinic acid should be introduced to the clinical practice in Czech Republic.

Effect of long-term administration of antidepressants on the lipid composition of brain plasma membranes

The connection between changes in lipid pattern in brain plasma membranes and long-term administration of therapeutically effective doses of antidepressants has not been sufficiently demonstrated so far. Therefore, we analyzed effect of antidepressants that differ in pharmacological selectivity on membrane lipid composition in the rat brain tissue. Laboratory rats were given desipramine, maprotiline, citalopram, moclobemide or lithium for a 4-week period. We observed a significant decrease in phosphatidylethanolamine representation after administration of maprotiline, citalopram and moclobemide when compared with controls. Membrane cholesterol content was decreased after desipramine administration and increased after citalopram or lithium treatment. Electroneutral phospholipids were decreased after the administration of all tested antidepressants except for desipramine. Decrease in phosphatidylserine was found following long-term administration of maprotiline or desipramine; relative representation of phosphatidylinositol was reduced after lithium treatment. Statistically significant negative correlation between cholesterol and electroneutral phospholipids was discovered. Membrane microviscosity evaluated by fluorescence anisotropy of membrane probes was only slightly decreased after desipramine and increased after citalopram administration. Hypothesis was supported that changes in brain neurotransmission produced by antidepressants could be, at least partially, associated with adaptive changes in membrane cholesterol and phospholipids.

The influence of n-3 polyunsaturated fatty acids and very low calorie diet during a short-term weight reducing regimen on weight loss and serum fatty acid composition in severely obese women

Polyunsaturated fatty acids of n-3 series (n-3 PUFA) were shown to increase basal fat oxidation in humans. The aim of the study was to compare the effect of n-3 PUFA added to a very low calorie diet (VLCD), with VLCD only during three-week inpatient weight reduction. Twenty severely obese women were randomly assigned to VLCD with n-3 PUFA or with placebo. Fatty acids in serum lipid fractions were quantified by gas chromatography. Differences between the groups were determined using ANOVA. Higher weight (7.55+/-1.77 vs. 6.07+/-2.16 kg, NS), BMI (2.82+/-0.62 vs. 2.22+/-0.74, p<0.05) and hip circumference losses (4.8+/-1.81 vs. 2.5+/-2.51 cm, p<0.05) were found in the n-3 group as compared to the control group. Significantly higher increase in beta-hydroxybutyrate was found in the n-3 group showing higher ketogenesis and possible higher fatty acid oxidation. The increase in beta-hydroxybutyrate significantly correlated with the increase in serum phospholipid arachidonic acid (20:4n-6; r = 0.91, p<0.001). In the n-3 group significantly higher increase was found in n-3 PUFA (eicosapentaenoic acid, 20:5n-3, docosahexaenoic acid, 22:6n-3) in triglycerides and phospholipids. The significant decrease of palmitoleic acid (16:1n-7) and vaccenic acid (18:1n-7) in triglycerides probably reflected lower lipogenesis. A significant negative correlation between BMI change and phospholipid docosahexaenoic acid change was found (r = -0.595, p<0.008). The results suggest that long chain n-3 PUFA enhance weight loss in obese females treated by VLCD. Docosahexaenoate (22:6n-3) seems to be the active component.

Composition of plasma fatty acids and non-cholesterol sterols in anorexia nervosa

Anorexia nervosa is a model of simple starvation accompanied by secondary hyperlipoproteinemia. The pattern of plasma fatty acids influences the levels of plasma lipids and lipoproteins. The concentration of plasma lathosterol is a surrogate marker of cholesterol synthesis de novo, concentrations of campesterol and beta-sitosterol reflect resorption of exogenous cholesterol. The aim of the study was to evaluate fatty acids in plasma lipid classes and their relationship to plasma lipids, lipoproteins, cholesterol precursors and plant sterols. We examined 16 women with anorexia nervosa and 25 healthy ones. Patients with anorexia nervosa revealed increased concentrations of total cholesterol, triglycerides, HDL-cholesterol, campesterol and beta-sitosterol. Moreover, a decreased content of n-6 polyunsaturated fatty acids was found in all lipid classes. These changes were compensated by an increased content of monounsaturated fatty acids in cholesteryl esters, saturated fatty acids in triglycerides and both monounsaturated and saturated fatty acids in phosphatidylcholine. The most consistent finding in the fatty acid pattern concerned a decreased content of linoleic acid and a raised content of palmitoleic acid in all lipid classes. The changes of plasma lipids and lipoproteins in anorexia nervosa are the result of complex mechanisms including decreased catabolism of triglyceride-rich lipoproteins, normal rate of cholesterol synthesis and increased resorption of exogenous cholesterol.

Composition of plasma fatty acids and non-cholesterol sterols in anorexia nervosa

Anorexia nervosa is a model of simple starvation accompanied by secondary hyperlipoproteinemia. The pattern of plasma fatty acids influences the levels of plasma lipids and lipoproteins. The concentration of plasma lathosterol is a surrogate marker of cholesterol synthesis de novo, concentrations of campesterol and beta-sitosterol reflect resorption of exogenous cholesterol. The aim of the study was to evaluate fatty acids in plasma lipid classes and their relationship to plasma lipids, lipoproteins, cholesterol precursors and plant sterols. We examined 16 women with anorexia nervosa and 25 healthy ones. Patients with anorexia nervosa revealed increased concentrations of total cholesterol, triglycerides, HDL-cholesterol, campesterol and beta-sitosterol. Moreover, a decreased content of n-6 polyunsaturated fatty acids was found in all lipid classes. These changes were compensated by an increased content of monounsaturated fatty acids in cholesteryl esters, saturated fatty acids in triglycerides and both monounsaturated and saturated fatty acids in phosphatidylcholine. The most consistent finding in the fatty acid pattern concerned a decreased content of linoleic acid and a raised content of palmitoleic acid in all lipid classes. The changes of plasma lipids and lipoproteins in anorexia nervosa are the result of complex mechanisms including decreased catabolism of triglyceride-rich lipoproteins, normal rate of cholesterol synthesis and increased resorption of exogenous cholesterol.

[Insulin resistance, metabolic syndrome and cardiovascular diseases]

The article summarizes the nature and causes of the insulin resistance, its relation to the metabolic syndrome, and to the cardiovascular diseases. Insulin resistance can be defined as a set of abnormal clinical symptoms accompanied by lower tissue sensitivity to insulin. Metabolic syndrome, whose major components are impairments of glucose homeostase, obesity, dyslipidemia and arterial hypertension, represents an important risk factor for the development of diabetes mellitus type 2 and for the development of cardiovascular diseases. Possible factors, which can influence those relations, e.g., chronic inflammations, endothelial dysfunction and oxidation stress are discussed. The primary aims for the positive influencing the metabolic syndrome is the prevention of the development of diabetes mellitus type 2 and that of cardiovascular diseases. To approach those goals, the use of non-pharmacologic means (diet, appropriate physical activity) and pharmacologic (treatment of dyslipidemia, namely by statins and fibrates; management of hypertension, specifically by angiotensin-converging enzyme inhibitors, by angiotensin-receptor blockers, by glitazoe administration and by antithrombotic treatment) can be recommended.

[Effect of n-3 polyunsaturated fatty acids on plasma lipid, LDL lipoperoxidation, homocysteine and inflammation indicators in diabetic dyslipidemia treated with statin + fibrate combination]

BACKGROUND

The aim of the study was to determine how addition of n-3 polyenic fatty acids (PUFA) to the present treatment with statin + fibrate combination in diabetic dyslipidemia effects plasma lipids and lipoproteins, LDL lipoperoxidation, glucose homeostasis, concentration of serum homocysteine and selected inflammation indicators.

METHODS AND RESULTS

24 patients with type 2 diabetes, who after the combined hypolipidemic treatment (pravastatin 20 mg + micronized fenofibrate 200 mg per day) cannot reach the recommended target values for long time, received for three consecutive months supplementation of 3,6 g PUFA n-3 per day or a placebo (olive oil). At the beginning of the study, after three months of PUFA supplementation and after another three months of placebo administration, concentrations of plasma lipids, composition of fatty acids, plasma phosphatidylcholine (PC), cholesterol esters (CE) and triglycerides (TG), concentration of tHcy, conjugated diens (CD) in LDL and selected inflammation indicators (IL-6, TNFalpha, VCAM-1) were determined. n-3 PUFA supplementation resulted in the significant decrease of tHcy concentration (-29%, P < 0.01) and TG (-28%, P < 0.05) in plasma. During the period of placebo administration, values returned to base line levels. CD concentration in LDL after n-3 PUFA increased by 15% (P < 0.15, not significant), meanwhile after the placebo containing oleic acid it decreased by 18% (P < 0.05).

CONCLUSIONS

Our results show that n-3 PUFA supplementation together with statin + fibrate combination in DDL patients can significantly decrease the risk of cardiovascular diseases.

[Pathophysiology of and clinical significance of polyunsaturated fatty acids n-3 family]

Polyunsaturated fatty acids of n-3 family play an important role in the prevention of ischemic heart disease, as was shown in many epidemiological as well as intervention studies. These fatty acids are essential and human organism is fully dependent on their dietary intake from chloroplast of green plants and fat of aquatic animals. Cardioprotective action of these acids results from their complex effect (antiarrhytmic, antithrombotic, antiinflammatory, hypolipidemic etc.). These acids can, with the exception of glucose homeostasis, favourably influence individual components of the metabolic syndrome. Beneficial effects of n-3 polyunsaturated fatty acids are supposed also in chronic inflammatory and autoimmune diseases, psychiatric-neurological diseases and malignant tumours. In the case of rheumatoid arthritis, antiinflammatory effects of polyunsaturated fatty acids were proven. In general, favourable effects of the optimal income of n-3 polyunsaturated fatty acids can be explained by the influencing of cellular metabolic functions, incorporation into membrane phospholipids, modulation of enzymes and signal molecules as well as by direct impact on gene expression. Polyunsaturated fatty acids of n-3 family have high therapeutic potential, which results from the combined action on different levels of cell functions. In some diseases, their effect is nearly pharmacological - prevention of the sudden death and fatal myocardial infarction, treatment of hyper- and dyslipoproteinemias, suppression of the inflammatory activity in rheumatoid arthritis. In another group of diseases, they have supporting effect (prevention of the arterial hypertension in metabolic syndrome) and, finally, in the last one (psychiatric-neurological diseases and tumours), more data of defined clinical groups are necessary for final evaluation.

Higher content of 18:1 trans fatty acids in subcutaneous fat of persons with coronarographically documented atherosclerosis of the coronary arteries

AIM

To identify the total content of trans fatty acid (TFA) isomers and C18:1 trans isomers in subcutaneous fat samples from persons with atherosclerosis of the coronary arteries, as an indicator of dietary exposure.

METHODS

Using capillary gas chromatography, the authors determined total content of TFA isomers and C18:1 trans isomers in the subcutaneous fat of 34 patients with ischemic heart disease who had undergone aortocoronary bypass surgery and in 46 patients with no sign of coronary disease.

RESULTS

On average, the total TFAs in cardiac patients were 2.88 +/- 1.19% of all fatty acids, in noncardiac patients 2.56 +/- 0.89%. However, the difference is not statistically significant. The average concentration of C18:1 trans in cardiac patients (2.31 +/- 1.09%) was statistically significantly higher (p = 0.05) than in the noncardiac group (1.95 +/- 0.77%).

CONCLUSIONS

The results obtained indicate a lower TFA load in comparison with previous studies in other countries. A higher concentration of 18:1 TFAs in the subcutaneous fat of patients with coronary disease might be an impulse to correct the dietary habits of this very high-risk population.

Corticosteroid effect on Caco-2 cell lipids depends on cell differentiation

Previous studies from our laboratory have indicated that secondary hyperaldosteronism affects phospholipids of rat colonic enterocytes. To assess whether this represents a direct effect of mineralocorticoids on enterocytes, the role of aldosterone and dexamethasone in the regulation of lipid metabolism was examined in Caco-2 cells during development of their enterocyte phenotype. Differentiation of Caco-2 cells was associated with increased levels of triglycerides (TG) and cholesteryl esters (CE), a decreased content of cholesterol and phospholipids and changes in individual phospholipid classes. The phospholipids of differentiated cells had a higher content of n-6 polyunsaturated fatty acids (PUFA) and lower amounts of monounsaturated (MUFA) and saturated fatty acids than subconfluent undifferentiated cells. Differentiated cells exhibited a higher ability to incorporate [3H]arachidonic acid (AA) into cellular phospholipids and a lower ability for incorporation into TG and CE. Incubation of subconfluent undifferentiated cells with aldosterone or dexamethasone was without effect on the content of lipids, their fatty acids and [3H]AA incorporation. In contrast, aldosterone treatment of differentiated cells diminished the content of TG, increased the content of phospholipids and modulated their fatty acid composition. The percentage of n-6 and n-3 PUFA in phospholipids was increased and that of MUFA decreased, whereas no changes in TG were observed. The incorporation of [3H]AA into phospholipids was increased and into TG decreased and these changes were blocked by spironolactone. Treatment of differentiated cells with dexamethasone increased their CE content but no effect was identified upon other lipids, their fatty acid composition and on the incorporation of [3H]AA. As expected for the involvement of corticosteroid hormones the mineralocorticoid and glucocorticoid receptors were identified in Caco-2 cells by RT-PCR. The results suggest that aldosterone had a profound influence on lipid metabolism in enterocytes and that its effect depends on the stage of differentiation. The aldosterone-dependent changes occurring in phospholipids and their fatty acid composition may reflect a physiologically important phenomenon with long-term consequences for membrane structure and function.

[Lipid metabolism in anorexia nervosa]

BACKGROUND

Anorexia nervosa is a model of simple starvation accompanied by secondary hyperlipoproteinemia. Plasma fatty acid pattern influences levels of plasma lipids and lipoproteins. Level of plasma lathosterol represents a marker of cholesterol synthesis de novo; levels of plant sterols reflect resorption of exogenous cholesterol. The aim of the study was to evaluate fatty acids in plasma lipid classes and their relationships to plasma lipids, lipoproteins, lathosterol, campesterol and beta-sitosterol.

METHODS AND RESULTS

We examined 16 women with anorexia nervosa and 25 matched controls. Main lipid classes were separated by thin-layer chromatography, fatty acids and non-cholesterol sterols were evaluated by capillary gas chromatography. Patients with anorexia nervosa revealed increased concentrations of total cholesterol, triglycerides, HDL-cholesterol, campesterol and beta-sitosterol; changes in plasma levels of lathosterol did not reach statistical significance. The most consistent finding in fatty acid composition was a decreased content of linoleic acid and raised content of palmitoleic acid in all lipid classes.

CONCLUSIONS

Changes of plasma lipids and lipoproteins in anorexia nervosa result from complex mechanisms including increased synthesis of triglyceride-rich lipoproteins along with unchanged cholesterol synthesis rate. Hypercholesterolemia in anorexia nervosa may also result from increased resorption of exogenous cholesterol.

Treatment of hypertriglyceridemia with fenofibrate, fatty acid composition of plasma and LDL, and their relations to parameters of lipoperoxidation of LDL

The purpose of this study was to determine oxidation and oxidability of VLDL and LDL in connection with changes in their composition and content of FA in LDL after treatment with fenofibrate in patients with HTG.

The responses of serum and adipose Fatty acids to a one-year weight reduction regimen in female obese monozygotic twins

We have reported strong intrapair resemblances (IPRs) in serum phosphatidylcholine (PC) fatty acid composition within adult monozygotic twins living apart. This study assessed the contribution of genetic factors to changes in serum and adipose tissue fatty acids resulting from weight loss and followed by a subsequent year of weight maintenance. Eleven pairs of female obese monozygotic twins (age: 38.9 +/- 1.8; BMI: 32.5 +/- 0.9) were recruited for the study. Fasting serum and adipose tissue were obtained after 1 week of inpatient stabilization, after 1 month of inpatient very-low-calorie diet (VLCD), and again after 1 year of outpatient weight maintenance. Fatty acids in serum lipid fractions and adipose tissue were quantitated by gas chromatography. Using multiple regression adjusted for age and initial value, IPRs were determined for the changes induced by VLCD and by the year of weight maintenance. There were few IPRs in nonessential fatty acids. By contrast, there were numerous IPRs for essential fatty acids (EFA), especially in the n-3 family across the VLCD. Following the maintenance year, however, frequent IPRs for nonessential fatty acids were seen, particularly in serum PC, and strong IPRs were seen for 18:3 n-3 and 20:5 n-3 across multiple fractions. These results infer the existence of strong genetic factors determining both the nonessential and EFA compositions of tissue lipids in humans independent of diet. Of particular note were the consistent IPRs for n-3 fatty acids despite dietary stress, indicating that the conservation and distribution of this EFA family are subject to considerable genetic variance in humans.

Effect of column and software on gas chromatographic determination of fatty acids

Four capillary columns (A: CP-WAX 52 CB 25 m x 0.25 mm; B: CP WAX 52 CB 30 m x 0.25 mm; C: CP-WAX 58 CB 25 m x 0.25 mm, Chrompack; D: OMEGAWAX 320 30 m x 0.32 mm, Supelco) and two integration software (Mosaic v.5.10, Chrompack and CSW v.1.7, Data Apex5) were compared for analysis of fatty acids. Column A was mounted stepwise in two different instruments. Fatty acids of blood plasma phosphatidylcholine and standard mixture of saturated fatty acids were analysed as methyl esters under identical chromatographic conditions. Both integrating software did not differ significantly in most results; differences were observed only for minor components: 16:1n9 (0.10+/-0.020 vs. 0.17 +/- 0.005 M%, P < 0.0001, column Al; 0.09 +/- 0.011 vs. 0.16 +/- 0.007 M%, P< 0.0001, column A2; 0.09 +/- 0.010 vs. 0.17 +/- 0.003 M%, P < 0.0001, column C; 0.09 +/ -0.008 vs. 0.19 +/- 0.003 M%, P < 0.0001, column D), 20:0 (0.10+0.001 vs. 0.06 +/- 0.005 M%, P < 0.05, column C) and 20:2n6 (0.43 +/- 0.030 vs. 0.91 +/- 0.016 M%, P < 0.0001, column A2). Increased values for 16:1n9 and 20:2n6 integrated by MOSAIC are caused by cointegration of two poorly resolved peaks: fatty acid and impurity from sample matrix. Lower values for 20:0 are caused by incomplete integration of minor peak. Differences between columns were observed mostly for minor fatty acids. The results indicate that CSW is more suitable software for integration of complicated chromatograms. Linear calibration dependences measured with standard mixture of saturated fatty acids (carbon number 10-24) were observed in wide range of concentrations (three orders). Slope close to unity and minimal value of intercept confirmed theoretical relations when analyses are run under optimal conditions. Use of one column is advisable in small intervention or experimental metabolic studies.

[Effect of fibrates on VLDL and LDL lipoprotein composition and parameters of their oxidation in hypertriglyceridemia]

BACKGROUND

Meta-analyses of epidemiological studies proved that hypertriacylglycerolemia (HTAG) is an independent CHD risk factor. The VLDL lipoproteins, which are the main TAG carrier, are precursors of atherogenic LDL and their increased concentration is related to the decrease of antiatherogenic HDL, increased ratio of small, dense LDL and represents one of the causes of the endothelial dysfunction. According to some authors, HTAG is one of the factors of the oxidation stress.

MATERIAL AND METHODS

45 patients of the studied group received 200 mg of micronized fenofibrate per day for six weeks. Before the beginning and after the end of treatment, following examinations were carried out: concentration of plasma lipids, lipoproteins, and apolipoproteins, composition of fatty acids (FA) in main lipid plasma classes and LDL (phosphatidylcholine--PC, TAG, cholesteryl esters--CE) and lipoperoxidation in VLDL and LDL, isolated by preparative ultracentrifugation.

RESULTS AND CONCLUSIONS

In plasma, the treatment of HTAG led to a significant decrease of TC, TAG and apo-B concentration and to the increase of cholesterol concentration in HDL and in both HDL2 and HDL3 subfractions. In isolated LDL particles we observed a decrease of the TAG portion (by 25%) together with significant lag phase prolongation (by 33%, P < 0.05) and peak time retardation (by 24%, P < 0.05). In VLDL particles the concentration of cholesterol became smaller (by 28%), TAG (by 26%), phospholipids (by 28%) (in all groups P < 0.005) and the lag phase became significantly longer (by 16%, P < 0.01). Treatment with fenofibrate significantly reduced the linoleic acid (18:2n-6) in PC and TAG plasma, CE and TG LDL, in a higher ratio of palmitoleic acid (16:1n-7) in CE LDL, oleic (18:1n-9) in PC LDL, in significant concentration of total monoenic FA in PC and CE LDL and to a significant increase of the concentration of myristic acid (14:0) in CE and myristic and stearic acids (18:0) in TAG LDL. From our results it is possible to conclude that the six-week long treatment of HTAG with micronized phenofibrate led to significant modification of LDL and VLDL composition accompanied by their lower lipoperoxidation indexes. These favourable changes in oxidability were accompanied with changes in the composition of FA in CE, TAG and PC plasma as well as LDL.

[Effect of nutrition on adipose tissue metabolism in humans]

Lipolysis in adipose tissue and balance between energy intake and expenditure are involved in the regulation of adipose tissue mass. Several recent findings suggest that alterations in the regulation of lipolysis and/or energy balance might contribute to the development of obesity. Hormone-sensitive lipase and uncoupling proteins play important role in regulation of lipolysis in adipose tissue as well as in the regulation of energy balance of various tissues. Mechanisms of the control of expression of genes coding synthesis of these proteins are poorly known. A brief overview of the present knowledge of the effects of nutritional intervention on the regulation of lipolysis in adipose tissue and on the expression of genes of hormone-sensitive lipase and that of uncoupling proteins is given in this article. Results of the authors' studies on the effect of calorie restriction on gene expression in adipose tissue are presented.

[Fatty acid composition of domestic dietary fats]

Trans fatty acids (TFA) were analyzed by capillary gas chromatography in four groups of edible fats available on the Prague market. In animal fats, 1.9-2.5%, 2.8-5.5% and 11.3-13.5% TFA were found in the lard, butter, and butter enriched by vegetable fat, respectively. In shortenings, TFA content varied between 0.5 and 38%, in margarines from 0.6 to 13% and in table fats from 1.4 to 27%.

[Insulinemia, fatty acids in plasma lipids and lipoproteins and oxidation of VLDL and LDL in hyperlipidemia]

Both insulin resistance and hyperlipidaemia are connected with an increased oxidative stress, playing a significant role in the development of atherosclerosis. A significant event in the process being the oxidative modification of the lipoproteins, especially LDL. Aim of the study was to analyse relationships between the fatty acid composition of the plasma cholesteryl esters (CE), triglycerides (TG) and phosphatidylcholine (PC) and of the separated LDL, insulinaemia and oxidability of both VLDL and LDL particles. We have observed the group of 75 patients with hyperlipidaemia (52 men and 23 women), which was divided in the two subgroups after the basal insulinaemia (more resp. less than 13 mU/l). Fasting hyperinsulinaemia of the probands with normal glucose tolerance served as a marker of an insulin resistance. Patients with both hyperlipidaemia and basal hyperinsulinaemia were characterized by a significantly higher concentration of TG, apolipoprotein B in LDL, and lower concentration of cholesterol in HDL, especially in HDL3. We have observed only marginally significant elevation of concentration of the dihomo-gammalinolenic acid (DGLA) in plasma PC and also higher concentrations of alpha-linolenic and lower of arachidonic acid (AA) and in LDL-CE in the hyperinsulinaemic group. We have also found significantly positive correlations between the stearic acid in plasma PC, alpha-linolenic acid in plasma TG on one hand and the basal insulinaemia on the other hand. Significant positive correlation was also found between the ratio docosahexaenoic/docosapentaenic acid and insulinaemia in 120 min of oral glucose tolerance test. Significant negative correlation was observed between the ratio AA/DGLA and basal insulinaemia. Analysing the lipoperoxidation of VLDL and LDL using the method of conjugated diene kinetics we have found statistically non-significant decrease of lag phase duration of LDL and VLDL (their oxidability).

[Effect of fat distribution on lipoprotein composition and parameters of lipoperoxidation]

Fat distribution, not overweight and obesity per se, are supposed to be associated with hemodynamic, hemostatic and other metabolic disturbances (insulin resistance, hyperuricemia and dyslipidemia). Moreover, obesity increases the total risk of cardiovascular disease. Oxidative modification of lipoproteins, especially of LDL, is supposed to play a key role in the initiation and progression of atherosclerosis. Therefore we analysed VLDL a LDL composition and Cu(2+)-catalyzed conjugated diene formation in both lipoprotein fractions in patients with intraabdominal fat accumulation and in control group. Patients (33, 12 M/21 F) with intraabdominal fat accumulation (WHCR 1.00 for men, 0.85 for women) revealed, in comparison with control group (72, 47 M/25 F), after adjustment for the same age, increased plasma total cholesterol, apolipoprotein B, non-esterified fatty acid concentrations, and systolic blood pressure as well. In the group of patients increased levels of cholesterol, triglycerides, phospholipids, proteins and apolipoprotein B (only in the fraction of VLDL) were found in the both VLDL and LDL fractions. In this group of patients increased concentrations of conjugated dienes in VLDL and decreased length of lag phase of VLDL were found. Parameters of conjugated diene formation of LDL (basal absorbance, length of lag phase, propagation phase) did not differ significantly from controls. Concomitantly, persons with intraabdominal fat distribution showed decreased titres of antibodies against oxidative modified LDL. The results indicated that the patients with intraabdominal fat accumulation revealed not only adverse composition of VLDL and LDL particles, but also increased VLDL oxidation and oxidability.

Low-salt diet alters the phospholipid composition of rat colonocytes

The effect of low-salt diet on phospholipid composition and remodeling was examined in rat colon which represents a mineralocorticoid target tissue. To elucidate this question, male Wistar rats were fed a low-salt diet and drank distilled water (LS, low-salt group) or saline instead of water (HS, high-salt group) for 12 days before the phospholipid concentration and fatty acid composition of isolated colonocytes were examined. The dietary regimens significantly influenced the plasma concentration of aldosterone which was high in LS group and almost zero in HS group. Plasma concentration of corticosterone was unchanged. When expressed in terms of cellular protein content, a significantly higher concentration of phospholipids was found in LS group, with the exception of sphingomyelin (SM) and phosphatidylserine (PS). Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) accounted for more than 70% of total phospholipids in both groups. A comparison of phospholipid distribution in LS and HS groups demonstrated a higher percentage of PE and a small, but significant, decrease of PC and SM in LS group. The percentage of phosphatidylinositol (PI), PS and cardiolipin (CL) were not affected by mineralocorticoid treatment. With respect to the major phospholipids (PE, PC), a higher level of n-6 polyunsaturated fatty acids (PUFA) and lower levels of monounsaturated fatty acids were detected in PC of LS group. The increase of PUFA predominantly reflected an increase in arachidonic acid by 53%. In comparison to the HS group, oleic acid content was decreased in PC and PE isolated from colonocytes of the LS group. Our data indicate that alterations in phospholipid concentration and metabolism can be detected in rats with secondary hyperaldosteronism. The changes in phospholipid concentration and their fatty acid composition during fully developed effect of low dietary Na+ intake may reflect a physiologically important phenomenon with long-term consequences for membrane structure and function.