Capillary gas chromatographic profiling of total long-chain fatty acids and cholesterol in biological materials

Albumin-bound fatty acids induce mitochondrial oxidant stress and impair antioxidant responses in proximal tubular cells

Albumin induces oxidative stress and cytokine production in proximal tubular cells (PTECs). Albumin-bound fatty acids (FAs) enhance tubulopathic effects of albumin in vivo. We proposed that FA aggravation of albumin-induced oxidative stress in PTECs might be involved. We hypothesized that mitochondria could be a source of such stress. Using a fluorescent probe, we compared reactive oxygen species (ROS) production after exposure of PTECs to bovine serum albumin (BSA) alone or loaded with oleic acid (OA-BSA) (3-30 g/l for 2 h). There was no difference in cellular albumin uptake, but OA-BSA dose-dependently induced more ROS than BSA alone (P<0.001). OA-BSA-induced ROS was significantly alleviated by mitochondrial inhibition, but not by inhibitors of nicotinamide adenine dinucleotide phosphate hydrogenase (NADPH) oxidase, xanthine oxidase, or nitric oxide synthase. Gene expression analysis showed that neither the NADPH oxidase component p22phox nor xanthine oxidase was induced by BSA or OA-BSA. OA-BSA, in contrast to BSA, failed to induce mitochondrial manganese superoxide dismutase 2 (SOD2) expression. OA-BSA showed a greater capacity than BSA to downregulate heme oxygenase-1 mRNA expression and accentuate inflammatory cytokine mRNA and protein. Supplementation of SOD activity with EUK-8 reduced ROS, and interleukin-6 protein expression was suppressed by both mitochondrial inhibition and SOD augmentation. Thus, in PTECs, FAs accentuate albumin-induced oxidative stress and inflammatory cytokine expression via increased mitochondrial ROS, while frustrating protective antioxidant responses.

Relationship between umbilical cord essential fatty acid content and the quality of general movements of healthy term infants at 3 months

Prenatal essential fatty acid (EFA) status might be an important factor in the development of the central nervous system (CNS). The aim of the present study was to evaluate the relationship between the fatty acid compositions of the umbilical blood vessels at birth, used as a proxy of prenatal EFA status, and quality of general movements (GMs) at 3 mo. Umbilical artery and vein fatty acid compositions were investigated in a mixed group of breastfed infants and infants fed with formula with or without long-chain polyunsaturated fatty acid (LCPUFA) supplementation. At the age of 3 mo, video assessment of the quality of GMs was performed to evaluate neurologic condition. The quality of GMs was scored by assessing the degree of variation, complexity, and fluency. Outcomes were classified as normal-optimal, normal suboptimal, mildly abnormal, and definitely abnormal movements. Information on potential confounders, including the type of postnatal feeding, was collected prospectively. Associations between fatty acid status at birth and quality of GMs were investigated, and multinomial logistic regression analyses were carried out. None of the infants showed definitely abnormal movements. Infants with mildly abnormal GMs had a lower EFA index, lower arachidonic acid (AA) content, higher total n-9 fatty acid, and higher total monounsaturated fatty acid (MUFA) content in the umbilical artery compared with infants with normal GMs. Multivariate analyses confirmed these findings. We conclude that mildly abnormal GMs are associated with a less favorable EFA status in the umbilical artery.

Erythrocyte membrane fatty acids in benign and progressive forms of multiple sclerosis

BACKGROUND

There is no good explanation why a proportion of patients with multiple sclerosis (MS) have a relatively benign form of the disease. An imbalance between saturated and unsaturated fatty acids (FA) might influence the disease course of MS.

AIM

To assess whether the erythrocyte membrane fatty acid composition, which is a biological marker of long term dietary FA consumption, is different between patients with benign and progressive MS.

METHODS

The erythrocyte membrane FA composition was measured by gas chromatography in 23 healthy controls, 27 patients with benign MS, 32 patients with secondary progressive MS and 23 patients with primary progressive MS. None of the patients was following a special diet.

RESULTS

No significant differences in levels of saturated and unsaturated FA or in omega-3- and omega-6-polyunsaturated FA were found between controls and patients with the different subtypes of MS.

CONCLUSION

Our data suggest that factors other than dietary fatty acid consumption are responsible for the different disease courses of MS.

Low essential fatty acid and B-vitamin status in a subgroup of patients with schizophrenia and its response to dietary supplementation

We assessed essential fatty acid (EFA) and B-vitamin status, together with their determinants, in 61 patients with schizophrenia and established whether those with poor status responded biochemically to the appropriate dietary supplements. As a group, the patients had high erythrocyte saturated fatty acids (FAs), monounsaturated FA and low polyunsaturated FA of the omega3 and omega6 series. Patients reporting not to take vitamin supplements had low vitamin B12 and high homocysteine. Homocysteine variance proved best explained by folate in both the total group and male patients, and by vitamins B12 and B6 in females. Alcohol consumption and duration of illness are risk factors for low polyunsaturated FA status (< P2.5 of reference range), while male gender and absence of fish consumption predict hyperhomocysteinemia (> P97.5 of reference range). Two patients exhibited biochemical EFA deficiency and seven showed biochemical signs of omega3/docosahexaenoic acid (DHA) marginality. Four patients exhibited moderate hyperhomocysteinemia with plasma values ranging from 57.5 to 74.8 micromol/L. None of the five patients with either moderate hyperhomocysteinemia, biochemical EFA deficiency, or both, was predicted by their clinicians to have poor diets. That diet was nevertheless at the basis of these abnormalities became confirmed after supplementing 4 of them with B vitamins and with soybean and fish oils. We conclude that a subgroup of patients with schizophrenia has biochemical EFA deficiency, omega3/DHA marginality, moderate hyperhomocysteinemia, or combinations. Correction seems indicated in view of the possible relation of poor EFA and B-vitamin status with some of their psychiatric symptoms, but notably to reduce their high risk of cardiovascular disease.

Addition of oleic acid to delipidated bovine serum albumin aggravates renal damage in experimental protein-overload nephrosis

BACKGROUND

Non-esterified fatty acids (NEFA) carried on albumin may have a causal role in the development of chronic proteinuria-induced nephropathy. To investigate whether NEFA aggravate renal structural damage, we studied the effects of NEFA addition to delipidated bovine serum albumin (BSA) in protein-overload nephropathy.

METHODS

Three groups of Wistar rats received daily intraperitoneal injections (3 weeks) of either 1 g NEFA-free BSA (BSA-0), or NEFA-free BSA with three (BSA-3) or six (BSA-6) molecules oleic acid added per BSA molecule. An additional group received saline injections only (SAL). Renal damage was evaluated by immunohistochemistry and RT-PCR.

RESULTS

Interstitial and glomerular alpha-smooth muscle actin (alpha-SMA, marker of myofibroblast transformation) expression were higher in BSA-3/6 than in saline-injected controls (P < 0.001). Glomerular macrophage influx and desmin (marker of glomerular epithelial cell damage) expression were higher in all BSA-injected rats than SAL (P < 0.001). Interstitial macrophage influx was elevated in BSA-0/3 (P < 0.05) and BSA-6 (P < 0.001) compared to SAL. Addition of six molecules of oleic acid to BSA revealed higher interstitial and glomerular alpha-SMA expression (P < 0.001), increased interstitial macrophage numbers (P < 0.001) and enhanced glomerular desmin expression (P < 0.05) compared to BSA-0. RT-PCR revealed higher glomerular alpha-SMA mRNA expression in BSA-3/6 than SAL (P < 0.001 and 0.05, respectively), interstitial alpha-SMA mRNA was elevated in BSA-6 (P < 0.05). Interstitial TGF-beta1 mRNA expression was significantly higher in BSA-3 than SAL (P < 0.05).

CONCLUSIONS

These data show that addition of oleic acid to NEFA-free BSA aggravates renal damage, suggesting a role for NEFA in the pathogenesis of proteinuric nephropathies.

Essential fatty acid deficiency in mice is associated with hepatic steatosis and secretion of large VLDL particles

Essential fatty acid (EFA) deficiency in mice decreases plasma triglyceride (TG) concentrations and increases hepatic TG content. We evaluated in vivo and in vitro whether decreased hepatic secretion of TG-rich very low-density lipoprotein (VLDL) contributes to this consequence of EFA deficiency. EFA deficiency was induced in mice by feeding an EFA-deficient (EFAD) diet for 8 wk. Hepatic VLDL secretion was quantified in fasted EFAD and EFA-sufficient (EFAS) mice using the Triton WR-1339 method. In cultured hepatocytes from EFAD and EFAS mice, VLDL secretion into medium was measured by quantifying [(3)H]-labeled glycerol incorporation into TG and phospholipids. Hepatic expression of genes involved in VLDL synthesis and clearance was measured, as were plasma activities of lipolytic enzymes. TG secretion rates were quantitatively similar in EFAD and EFAS mice in vivo and in primary hepatocytes from EFAD and EFAS mice in vitro. However, EFA deficiency increased the size of secreted VLDL particles, as determined by calculation of particle diameter, particle sizing by light scattering, and evaluation of the TG-to-apoB ratio. EFA deficiency did not inhibit hepatic lipase and lipoprotein lipase activities in plasma, but increased hepatic mRNA levels of apoAV and apoCII, both involved in control of lipolytic degradation of TG-rich lipoproteins. EFA deficiency does not affect hepatic TG secretion rate in mice, but increases the size of secreted VLDL particles. Present data suggest that hypotriglyceridemia during EFA deficiency is related to enhanced clearance of altered VLDL particles.

High contents of both docosahexaenoic and arachidonic acids in milk of women consuming fish from lake Kitangiri (Tanzania): targets for infant formulae close to our ancient diet?

Current recommendations for arachidonic (AA) and docosahexaenoic (DHA) acids in infant formulae are based on milk of Western mothers. Validity may be questioned in view of the profound dietary changes in the past 100 years, as opposed to our slowly adapting genome. Hominin evolution occurred in the proximity of East-African freshwater lakes and rivers and early homo sapiens had higher intakes of AA and DHA from a predominantly lacustrine-based diet. In search of milk AA and DHA contents of our African ancestors, we investigated the milk of 29 lactating women living in Doromoni near lake Kitangiri (Tanzania). They consumed sunflower oil-fried local fish as only animal lipid sources, maize and local vegetables. AA and DHA contents of Doromoni milk may be close to that of early homo sapiens, because of the similarity of their life-long consumption of East-African lacustrine-based foods. Human milk fatty acid relationships from our historical worldwide database and the literature revealed that disparities between the Doromoni diet and the presumed ancient diet (i.e. higher carbohydrate and linoleic acid intakes) are unlikely to affect milk AA and DHA contents. Doromoni milk had high contents of AA (median 0.70 mol%), DHA (0.75) and eicosapentaenoic acid (EPA, 0.17), and low AA/DHA ratios (median 0.91; 0.55-2.61). This tracks down to consumption of fish with high AA and DHA contents, and AA/EPA ratios. We conclude that the milk AA, DHA and EPA contents of Doromoni women might provide us with clues to optimize infant formulae and perhaps the milk of Western women.

Lower fetal status of docosahexaenoic acid, arachidonic acid and essential fatty acids is associated with less favorable neonatal neurological condition

Long-chain polyunsaturated fatty acids, notably arachidonic (AA) and docosahexaenoic (DHA) acids are abundant in brain and may be conditionally essential in fetal life. We investigated umbilical artery (UA) and vein (UV) fatty acid compositions and early neonatal neurological condition in 317 term infants. Neurological condition was summarized as a clinical classification and a 'neurological optimality score' (NOS). Neurologically abnormal infants (n=27) had lower UV DHA and essential fatty acid (EFA) status. NOS correlated positively with AA (UV), and EFA (UV) and DHA status (UV and UA) and negatively with 18:2omega6 and omega9 (UV), and 20:3omega9, omega7 and C18 trans fatty acids (UV and UA). UV DHA, AA, saturated fatty acids, gestational age and obstetrical optimality score explained 16.2% of the NOS variance. Early postnatal neurological condition seems negatively influenced by lower fetal DHA, AA and EFA status. C18 trans fatty acids and 18:2omega6 may exert negative effects by impairment of LCP status.

No indications for altered essential fatty acid metabolism in two murine models for cystic fibrosis

A deficiency of essential fatty acids (EFA) is frequently described in cystic fibrosis (CF), but whether this is a primary consequence of altered EFA metabolism or a secondary phenomenon is unclear. It was suggested that defective long-chain polyunsaturated fatty acid (LCPUFA) synthesis contributes to the CF phenotype. To establish whether cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction affects LCPUFA synthesis, we quantified EFA metabolism in cftr-/-CAM and cftr+/+CAM mice. Effects of intestinal phenotype, diet, age, and genetic background on EFA status were evaluated in cftr-/-CAM mice, DeltaF508/DeltaF508 mice, and littermate controls. EFA metabolism was measured by 13C stable isotope methodology in vivo. EFA status was determined by gas chromatography in tissues of cftr-/-CAM mice, DeltaF508/DeltaF508 mice, littermate controls, and C57Bl/6 wild types fed chow or liquid diet. After enteral administration of [13C]EFA, arachidonic acid (AA) and docosahexaenoic acid (DHA) were equally 13C-enriched in cftr-/-CAM and cftr+/+CAM mice, indicating similar EFA elongation/desaturation rates. LA, ALA, AA, and DHA concentrations were equal in pancreas, lung, and jejunum of chow-fed cftr-/-CAM and DeltaF508/DeltaF508 mice and controls. LCPUFA levels were also equal in liquid diet-weaned cftr-/-CAM mice and littermate controls, but consistently higher than in age- and diet-matched C57Bl/6 wild types. We conclude that cftr-/-CAM mice adequately absorb and metabolize EFA, indicating that CFTR dysfunction does not impair LCPUFA synthesis. A membrane EFA imbalance is not inextricably linked to the CF genotype. EFA status in murine CF models is strongly determined by genetic background.

Treatment of EFA deficiency with dietary triglycerides or phospholipids in a murine model of extrahepatic cholestasis

Essential fatty acid (EFA) deficiency during cholestasis is mainly due to malabsorption of dietary EFA (23). Theoretically, dietary phospholipids (PL) may have a higher bioavailability than dietary triglycerides (TG) during cholestasis. We developed murine models for EFA deficiency (EFAD) with and without extrahepatic cholestasis and compared the efficacy of oral supplementation of EFA as PL or as TG. EFAD was induced in mice by feeding a high-fat EFAD diet. After 3 wk on this diet, bile duct ligation was performed in a subgroup of mice to establish extrahepatic cholestasis. Cholestatic and noncholestatic EFAD mice continued on the EFAD diet (controls) or were supplemented for 3 wk with EFA-rich TG or EFA-rich PL. Fatty acid composition was determined in plasma, erythrocytes, liver, and brain. After 4 wk of EFAD diet, induction of EFAD was confirmed by a sixfold increased triene-to-tetraene ratio (T/T ratio) in erythrocytes of noncholestatic and cholestatic mice (P < 0.001). EFA-rich TG and EFA-rich PL were equally effective in preventing further increase of the erythrocyte T/T ratio, which was observed in cholestatic and noncholestatic nonsupplemented mice (12- and 16-fold the initial value, respectively). In cholestatic mice, EFA-rich PL was superior to EFA-rich TG in decreasing T/T ratios of liver TG and PL (each P < 0.05) and in increasing brain PL concentrations of the long-chain polyunsaturated fatty acids (LCPUFA) docosahexaenoic acid and arachidonic acid (each P < 0.05). We conclude that oral EFA supplementation in the form of PL is more effective than in the form of TG in increasing LCPUFA concentrations in liver and brain of cholestatic EFAD mice.

Maternal and umbilical fatty acid status in relation to maternal diet

The aim of this study was to describe the dietary fat intake during pregnancy and to study the relationship between the intake of polyunsaturated fatty acids (PUFAs) and the fatty acid composition of maternal and umbilical plasma phospholipids (PLs) and cholesterol esters (CEs) at delivery. In addition, the contribution of food groups to the intake of total fat and fatty acids in the diet was quantified.Maternal and umbilical blood samples were collected at delivery from 30 healthy pregnant women. The women completed a food frequency questionnaire during the first and third trimesters. The total fat intake during pregnancy is 85 (SD 24) g/day. The mean intake of saturated fatty acids (SFAs) is 33.4 g/day, of monounsaturated fatty acids (MUFAs) 28.6 g/day and of PUFA 15.2 g/day. Major sources of fat, MUFA and PUFA are fats, oils and sauces. Major sources of SFA are meat and poultry followed by cheese and eggs. Meat and poultry contribute the most to the intake of 20:4n-6 whereas fish is the major source of 20:5n-3 (EPA) and 22:6n-3 (docosahexaenoic acid (DHA)) in the diet. Linoleic acid, EPA and DHA (w%) in PL of maternal plasma are positively related to the intake of these fatty acids during pregnancy. No association is found between the maternal intake of the two parent essential fatty acids (18:2n-6 and 18:3n-3) and their fraction in umbilical PL or CE. EPA and the sum of n-6 fatty acids (w%) in umbilical plasma PL are positively correlated with the dietary intake of these fatty acids.

Assessment of essential fatty acid and omega3-fatty acid status by measurement of erythrocyte 20:3omega9 (Mead acid), 22:5omega6/20:4omega6 and 22:5omega6/22:6omega3

BACKGROUND

Early suspicion of essential fatty acid deficiency (EFAD) or omega3-deficiency may rather focus on polyunsaturated fatty acid (PUFA) or long-chain PUFA (LCP) analyses than clinical symptoms. We determined cut-off values for biochemical EFAD, omega3-and omega3/22:6omega3 [docosahexaenoic acid (DHA)]-deficiency by measurement of erythrocyte 20:3omega9 (Mead acid), 22:5omega6/20:4omega6 and 22:5omega6/22:6omega3, respectively.

METHODS

Cut-off values, based on 97.5 percentiles, derived from an apparently healthy omnivorous group (six Dominica breast-fed newborns, 32 breast-fed and 27 formula+LCP-fed Dutch low-birth-weight infants, 31 Jerusalem infants, 33 Dutch 3.5-year-old infants, 69 omnivorous Dutch adults and seven Dominica mothers) and an apparently healthy group with low dietary LCP intake (81 formula-fed Dutch low-birth-weight infants, 12 Dutch vegans). Cut-off values were evaluated by their application in an EFAD suspected group of 108, mostly malnourished, Pakistani children, three pediatric patients with chronic fat-malabsorption (abetal-ipoproteinemia, congenital jejunal and biliary atresia) and one patient with a peroxisomal beta-oxidation disorder.

RESULTS

Erythrocyte 20:3omega9, 22:5omega6/20:4omega6 and 22:5omega6/22:6omega3 proved age-dependent up to 0.2 years. Cut-off values for ages above 0.2 years were: 0.46mol% 20:3omega9 for EFAD, 0.068mol/mol 22:5omega6/20:4omega6 for omega3-deficiency, 0.22mol/mol 22:5omega6/22:6omega3 for omega3/DHA-marginality and 0.48mol/mol 22:5omega6/22:6omega3 for omega3/DHA-deficiency. Use of RBC 20:3omega9 and 22:5omega6/20:4omega6 cut-off values identified 20.4% of the Pakistani subjects as EFAD+omega3-deficient, 12.9% as EFAD+omega3-sufficient, 38.9% as EFA-sufficient+omega3-deficient and 27.8% as EFA-sufficient+omega3-sufficient. The patient with the peroxisomal disorder was classified as EFA-sufficient, omega3-sufficient (based on RBC 22:5omega6/20:4omega6) and omega3/DHA-deficient (based on RBC 22:5omega6/22:6omega3). The three other pediatric patients were classified as EFAD, omega3-deficient and omega3/DHA-deficient.

CONCLUSION

Use of the combination of the present cut-off values for EFA, omega3 and omega3/DHA status assessment, as based on 97.5 percentiles, may serve for PUFA supplement intervention until better concepts have emerged.

Trans isomeric octadecenoic acids are related inversely to arachidonic acid and DHA and positively related to mead acid in umbilical vessel wall lipids

Long-chain PUFA play an important role in early human neurodevelopment. Significant inverse correlations were reported between values of trans isomeric and long-chain PUFA in plasma lipids of preterm infants and children aged 1-15 yr as well as in venous cord blood lipids of full-term infants. Here we report FA compositional data of cord blood vessel wall lipids in 308 healthy, full-term infants (gestational age: 39.7 +/- 1.2 wk, birth weight: 3528 +/- 429 g, mean +/- SD). The median (interquartile range) of the sum of 18-carbon trans FA was 0.22 (0.13) % w/w in umbilical artery and 0.16 (0.10) % w/w in umbilical vein lipids. Nonparametric correlation analysis showed significant inverse correlations between the sum of 18-carbon trans FA and both arachidonic acid and DHA in artery (r = -0.38, P < 0.01, and r = -0.20, P < 0.01) and vein (r = -0.36, P < 0.01, and -0.17, P < 0.01) wall lipids. In addition, the sum of 18-carbon trans FA was significantly positively correlated to Mead acid, a general indicator of EFA deficiency, in both artery (r = +0.35, P < 0.01) and vein (r = +0.31, P< 0.01) wall lipids. The present results obtained in a large group of full-term infants suggest that maternal trans FA intake is inversely associated with long-chain PUFA status of the infant at birth.

Estimated biological variation of the mature human milk fatty acid composition

We estimated the biological variation (CV(biol)) of 28 fatty acids (FA) in 465 mature human milk samples from The Netherlands, Caribbean, Jerusalem, Tanzania and Pakistan, by using data from the observed variation (CV(obs)) and analytical variation (CV(anal)). CV(biol) of the various regions was remarkably similar. The average CV(biol) of 455 samples, Pakistan excluded, ranged from 12.7% for 16:0 and 18.9% for 18:1 omega 9 to 68% for 22:6 omega 3 and about 100% for 20:5 omega 3. Those of 20:4 omega 6, 18:2 omega 6 and 18:3 omega 3 were 28.0, 33.0 and 37.3%, respectively. Because of the large CV(biol) and the many dietary changes in recent history, it seems impossible to consider the present human milk FA composition as the 'gold standard' for infant formula. Optimal human milk FA composition should rather derive from populations that consume traditional diets or from the scientific data that show the function of the individual FAs in neonatal development.

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.

Postprandial chylomicron clearance rate in late teenagers with diabetes mellitus type 1

A delayed chylomicron (CM) clearance rate, a known risk factor for atherosclerosis, has been described in adults with diabetes type 1 (DM1). We determined the CM clearance rate in late teenagers with DM1, and the relationship between CM clearance rate and elevated plasma lipid concentrations in DM1 teenagers in poor metabolic control (as characterized by HbA(1c) percentage). Plasma lipids and CM clearance were determined in nine patients with DM1 (mean age +/- SD: 17.5 +/- 0.6 y) and four healthy controls (mean age +/- SD: 20.1 +/- 0.8 y), by measuring breath (13)CO(2), plasma triglyceride, retinyl palmitate, and (13)C-labeled oleic acid concentrations, after oral administration of a fat-rich meal together with vitamin A and (13)C-oleic acid. In patients with DM1, fasting triglyceride and cholesterol concentrations were positively correlated with HbA(1c) percentage (p < 0.05). Neither in DM1 patients, nor in controls, was an elevated triglyceride concentration (above 1.7 mmol/L) found. Yet, in 22% of DM1 patients, cholesterol concentration was above 5.2 mmol/L, but not in any of the controls. CM clearance rate in DM1 patients was similar to that in controls and did not significantly correlate with HbA(1c) percentage. Fasting lipid concentrations in DM1 patients were not significantly correlated with CM clearance rate. Present data indicate that elevated lipid concentrations in late teenagers with DM1 are not attributable to a delay in CM clearance rate. A delayed CM clearance rate at late teenager age is not a risk factor contributing to the increased risk for atherosclerosis in DM1.

Effect of three low-dose fish oil supplements, administered during pregnancy, on neonatal long-chain polyunsaturated fatty acid status at birth

Adequate long-chain polyunsaturated fatty acid (LCP) status during pregnancy is important. We studied the effect of three low-dose fish oil supplements, administered during uncomplicated pregnancy, on neonatal LCP status at term delivery. Supplements were administered from the second trimester to delivery, either as fish oil capsules ("fish-1": 336 mg LCPomega3, n=15; and "fish-3": 1,008 mg LCPomega3, n=20) or milk-based supplement ("Mum": 528 mg LCPomega3, n=24). Fifty-seven untreated women served as controls. Fatty acids of umbilical veins (UV) and arteries (UA) were measured. The fish-1 group showed no differences, compared to controls. The Mum group had higher 20:5omega3, 22:5omega3, 22:6omega3, LCPomega3 and 22:6omega3/22:5omega6 in UV and UA. The fish-3 group had higher 22:5omega3 and 22:6omega3 (UA), LCPomega3 and 22:6omega3/22:5omega6 (UV and UA) and 20:3omega6 (UV). A 500-1000 mg daily LCPomega3 supplement, taken either as a milk-based supplement or fish oil capsules, effectively increases fetal LCPomega3 status, without affecting LCPomega6 status.

Effect of supplementation of arachidonic acid (AA) or a combination of AA plus docosahexaenoic acid on breastmilk fatty acid composition

We investigated whether supplementation with arachidonic acid (20:4 omega 6; AA), or a combination of AA and docosahexaenoic acid (22:6 omega 3; DHA) would affect human milk polyunsaturated fatty acid (PUFA) composition. Ten women were daily supplemented with 300 mg AA, eight with 300 mg AA, 110 mg eicosapentaenoic acid (20:5 omega 3; EPA) and 400 mg DHA, for one week and eight women served as unsupplemented controls. Milk samples were collected on days 0, 1 and 7. The fatty acid composition of the milk was analyzed by capillary gas chromatography with flame ionisation detection. Supplementation with AA alone had no effect on breastmilk AA, but tended to reduce EPA and DHA levels. Administration of a combination of AA, EPA and DHA tended to increase both milk AA and long chain PUFA (LCPUFA)omega 3 content. A larger simultaneous increase of milk AA, DHA and EPA than observed in the present study can probably be accomplished by the use of a combination of a lower LCPUFA omega 6/LCPUFA omega 3 ratio and higher AA, EPA and DHA dosages.

In humans, serum polyunsaturated fatty acid levels predict the response of proinflammatory cytokines to psychologic stress

BACKGROUND

Psychologic stress in humans induces the production of proinflammatory cytokines, such as interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), and interleukin-6 (IL-6), and that of the negative immunoregulatory cytokine, IL-10. An imbalance of omega6 to omega3 polyunsaturated fatty acids (PUFAs) in the peripheral blood causes an overproduction of proinflammatory cytokines. The omega3 PUFAs reduce the production of proinflammatory cytokines.

METHODS

This study examines whether an imbalance in omega6 to omega3 PUFAs in human blood predicts a greater production of proinflammatory cytokines in response to psychologic stress. Twenty-seven university students had serum sampled a few weeks before and after as well as 1 day before a difficult oral examination. We determined the omega6 and omega3 fractions in serum phospholipids as well as the ex vivo production of IFN-gamma, TNF-alpha, IL-6, IL-10, and IL-5 by diluted whole blood stimulated with polyclonal activators.

RESULTS

Academic examination stress significantly increased the ex vivo, stimulated production of IFN-gamma, TNF-alpha and IL-10, and the IFN-gamma/IL-5 production ratio. Subjects with lower serum omega3 PUFA levels or with a higher omega6/omega3 ratio had significantly greater stress-induced TNF-alpha and IFN-gamma responses than subjects with higher serum omega3 PUFAs and a lower omega6/omega3 ratio, respectively. Subjects with lower serum omega3 PUFA levels or with a higher omega6/omega3 ratio had a significantly higher stress-induced increase in the IFN-gamma/IL-5 ratio than the remaining subjects.

CONCLUSIONS

Psychologic stress induces a Th-1-like or proinflammatory response in some subjects. An imbalance in the omega6 to omega3 PUFA ratio appears to predispose humans toward an exaggerated Th-1-like response and an increased production of monocytic cytokines, such as TNF-alpha, in response to psychologic stress. The results suggest that increased omega3 PUFA levels may attenuate the proinflammatory response to psychologic stress.

Fish oil supplementation improves docosahexaenoic acid status of malnourished infants

AIM

To investigate whether the low docosahexaenoic acid (DHA) status of malnourished, mostly breast fed, Pakistani children can be improved by fish oil (FO) supplementation.

METHODS

Ten malnourished children (aged 8-30 months) received 500 mg FO daily for nine weeks. The supplement contained 62.8 mol% (314 mg) long chain polyunsaturated fatty acids of the omega3 series (LCPUFAomega3) and 22.5 mol% (112 mg) DHA. Seven FO unsupplemented children served as controls. Red blood cell (RBC) fatty acids were analysed at baseline and at the study end.

RESULTS

FO supplementation augmented mean (SD) RBC DHA from 2.27 (0.81) to 3.35 (0.76) mol%, without significantly affecting the concentrations of LCPUFAomega6. Unsupplemented children showed no RBC fatty acid changes. One FO supplemented child with very low initial RBC arachidonic acid showed a remarkable increase from 4.04 to 13.84 mol%, whereas another with high RBC arachidonic acid showed a decrease from 15.64 to 10.46 mol%.

CONCLUSION

FO supplementation improves the DHA status of malnourished children. The supplement is apparently well absorbed and not exclusively used as a source of energy.

Lowered omega3 polyunsaturated fatty acids in serum phospholipids and cholesteryl esters of depressed patients

Depression is associated with a lowered degree of esterification of serum cholesterol, an increased C20:4omega6/C20:5omega3 ratio and decreases in omega3 fractions in fatty acids (FAs) or in the red blood cell membrane. The aims of the present study were to examine: (i) serum phospholipid and cholesteryl ester compositions of individual saturated fatty acids (SFAs), monounsaturated FAs (MUFAs) and polyunsaturated FAs (PUFAs) in major depressed patients vs. healthy volunteers; (ii) the relationships between the above FAs and lowered serum zinc (Zn), a marker of the inflammatory response in depression; and (iii) the effects of subchronic treatment with antidepressants on FAs in depression. The composition of the FAs was determined by means of thin layer chromatography in conjunction with gas chromatography. Lipid concentrations were assayed by enzymatic colorimetric methods. The oxidative potential index (OPI) of FAs was computed in 34 major depressed inpatients and 14 normal volunteers. Major depression was associated with: increased MUFA and C22:5omega3 proportions and increased C20:4omega6/C20:5omega3 and C22:5omega6/C22:6omega3 ratios; lower C22:4omega6, C20:5omega3 and C22:5omega3 fractions in phospholipids; lower C18:3omega3, C20:5omega3 and total (sigma)omega3 FAs, and higher C20:4omega6/C20:5omega3 and sigmaomega6/sigmaomega3 ratios in cholesteryl esters; lower serum concentrations of phospholipids and cholesteryl esters; and a decreased OPI. In depression, there were significant and positive correlations between serum Zn and C20:5omega3 and C22:6omega3 fractions in phospholipids; and significant inverse correlations between serum Zn and the sigmaomega6/sigmaomega3, C20:4omega6/C20:5omega3, and C22:5omega6/C22:6omega3 ratios in phospholipids. There was no significant effect of antidepressive treatment on any of the FAs. The results show that, in major depression, there is a deficiency of omega3 PUFAs and a compensatory increase in MUFAs and C22:5omega6 in phospholipids. The results suggest that: (i) there is an abnormal metabolism of omega3 PUFAs in depression; (ii) the FA alterations in depression are related to the inflammatory response in that illness; and (iii) the disorders may persist despite successful antidepressant treatment.

Does supplementation of formula with evening primrose and fish oils augment long chain polyunsaturated fatty acid status of low birthweight infants to that of breast-fed counterparts?

We investigated whether formulae with evening primrose and fish oils raise long chain polyunsaturated fatty acids (LCPUFA) in plasma cholesterol esters (CE), erythrocytes (RBC) and platelets (PLT) to levels encountered in breast-fed infants. Low birthweight infants (< or =2500 g) received LCP1 formula (n = 16; 0.31% 18:3 omega6, 0.17% 20:5 omega3 and 0.20% 22:6 omega3) or LCP2 formula (n = 13; 0.32% 18:3 omega6, 0.34% 20:5 omega3 and 0.43% 22:6 omega3). Fatty acids were measured days 10+/-2, 20+/-3 and 42+/-3. The formulae raised CE, RBC and PLT 20:5 omega3 and 22:6 omega3 dose-dependently (P<0.01), to exceed levels of breast-fed babies (n = 18) day 42 (P<0.05). CE, RBC and PLT 20:3 omega6 was comparable with, and CE, RBC, PLT 20:4 omega6 were below, that of breast-fed infants (P<0.05). Dietary 20:5 omega3 and 22:6 omega3 related with CE, RBC and PLT 20:5 omega3 and 22:6 omega3 (n = 47; P< or =0.01). Dietary 20:5 omega3 and LCPUFA omega3 related inversely with CE, RBC and PLT 20:4 omega6 and LCPUFA omega6 (P< or =0.002). LCP1 and LCP2 fed infants had similar LCPUFA omega6 status day 42. Added 18:3 omega6 does not correct 20:4 omega6 to that of breast-fed infants, but improves 20:3 omega6 status. Fish oil dose-dependently raises 20:5 omega3 and 22:6 omega3, but decreases 20:4 omega6 and other LCPUFA omega6.

Umbilical vessels of preeclamptic women have low contents of both n-3 and n-6 long-chain polyunsaturated fatty acids

BACKGROUND

Preeclampsia is characterized by enhanced platelet aggregation and vasoconstriction and is related to an elevated ratio of thromboxane A2 to prostacyclin I2.

OBJECTIVE

We investigated whether altered eicosanoid production in preeclamptic women could be explained by the fatty acid composition of umbilical vessel walls and platelets.

DESIGN

The fatty acid composition of maternal and umbilical platelets and of umbilical arteries and veins in 27 preeclamptic women and 24 normotensive women was determined. Between-group differences were analyzed with linear discriminant analysis, the Kruskal-Wallis test, or analysis of covariance with gestational age as the covariate.

RESULTS

Platelets of preeclamptic women contained lower amounts of 20:5n-3 and a higher ratio of 20:4n-6 to 20:5n-3 than did platelets of normotensive women. Additionally, linear discriminant analysis revealed higher amounts of 20:4n-6 in platelets of preeclamptic women. Umbilical arteries and veins in preeclamptic women contained lower amounts of long-chain polyunsaturated fatty acids (PUFAs) of the n-3 series, n-6 long-chain PUFAs, and 20:3n-6 than did umbilical arteries and veins of normotensive women. Umbilical arteries also had lower amounts of 20:4n-6, higher amounts of 20:3n-9, and a higher ratio of 20:3n-9 to 20:4n-6.

CONCLUSIONS

Low amounts of long-chain n-3 and n-6 PUFAs in umbilical vessels of preeclamptic women with adequate n-6 status may indicate insufficient transplacental transfer of long-chain PUFAs. The low amounts of 20:4n-6, high amounts of 20:3n-9, and high ratio of 20:3n-9 to 20:4n-6 in umbilical arteries may unfavorably affect local prostacyclin production. Low amounts of 20:3n-6 in umbilical arteries and veins and low amounts of 20:5n-3 in maternal platelets may contribute to the dominance of eicosanoids derived from 20:4n-6.

Effects of malnutrition on the erythrocyte fatty acid composition and plasma vitamin E levels of Pakistani children

Erythrocyte fatty acids and plasma vitamin E concentrations were determined in 47 grade 2 and 21 grade 3 malnourished Pakistani children (ages 4-56 months). Data were compared with those of 26 age- and sex-matched apparently healthy controls. Evaluation with three statistical approaches revealed that both grade 2 and grade 3 malnourished children had decreased erythrocyte omega6 fatty acids and to a lesser extent decreased omega3 fatty acids. These decreases were compensated for by increased omega9 fatty acids. The patients tended to have lower plasma vitamin E concentrations. We conclude that malnourished Pakistani children have low essential fatty acid status, notably those of the omega6 series. The combination of low erythrocyte 22:6omega3 and a low 22:5omega6/22:4omega6 ratio in grade 2 patients suggests low delta4-desaturation activity, which may be due to impaired peroxisomal beta-oxidation.

Fatty acid composition in major depression: decreased omega 3 fractions in cholesteryl esters and increased C20: 4 omega 6/C20:5 omega 3 ratio in cholesteryl esters and phospholipids

Recently, there were some reports that major depression may be accompanied by alterations in serum total cholesterol, cholesterol ester and omega 3 essential fatty acid levels and by an increased C20: 4 omega 6/C20: 5 omega 3, i.e., arachidonic acid/eicosapentaenoic, ratio. The present study aimed to examine fatty acid composition of serum cholesteryl esters and phospholipids in 36 major depressed, 14 minor depressed and 24 normal subjects. Individual saturated (e.g., C14:0; C16:0, C18:0) and unsaturated (e.g., C18:1, C18:2, C20:4) fatty acids in phospholipid and cholesteryl ester fractions were assayed and the sums of the percentages of omega 6 and omega 3, saturated, branched chain and odd chain fatty acids, monoenes as well as the ratios omega 6/omega 3 and C20:4 omega 6/C20:5 omega 3 were calculated. Major depressed subjects had significantly higher C20:4 omega 6/C20:5 omega 3 ratio in both serum cholesteryl esters and phospholipids and a significantly increased omega 6/omega 3 ratio in cholesteryl ester fraction than healthy volunteers and minor depressed subjects. Major depressed subjects had significantly lower C18:3 omega 3 in cholesteryl esters than normal controls. Major depressed subjects showed significantly lower total omega 3 polyunsaturated fatty acids in cholesteryl esters and significantly lower C20:5 omega 3 in serum cholesteryl esters and phospholipids than minor depressed subjects and healthy controls. These findings suggest an abnormal intake or metabolism of essential fatty acids in conjunction with decreased formation of cholesteryl esters in major depression.

Gas chromatographic analysis of fatty acid methyl esters

The full process of fatty acid methyl ester (FAME) analysis consists of esterification of lipids, and of injection, separation, identification and quantitation of the FAMEs. In order for the required accuracy and precision to be attained, each of these steps has to be optimized. Esterification of lipids can be carried out with several reagents based on acid-catalysed or base-catalysed reactions. The advantages and disadvantages of these reagents are discussed. The most critical step in the gas chromatographic analysis of FAMEs is sample introduction. The classical split injection technique, which is the most widely used technique in the analysis of FAMEs, has the potential disadvantage of boiling-point-dependent sample discrimination. Cold injection of the sample, either on-column or by programmed-temperature vaporization, does not present this problem and should therefore be preferred. Modern, commercially available fused-silica capillary columns offer excellent separation of FAMEs from biological samples. Very polar stationary phases give excellent separation of all FAMEs but have relatively low thermal stability, resulting in long retention times. Non-polar phases have a much greater thermal stability but inferior selectivity. For many analyses, phases of intermediate polarity, which combine the advantages of a relatively high resolution capability with relatively high thermal stability, are the most suitable. FAMEs can be identified by comparison of their retention times with those of individual purified standards or secondary standards based on lipids that have been well characterized in literature. Relative retention times and equivalent chain-length values also provide useful information. FAMEs can be quantitated by peak areas via calibration factors, and absolute concentrations can be determined by adding an internal standard. Among numerous applications in biomedical research, the analysis of fatty acids from body tissues may contribute to the understanding of the link between the dietary intake of fatty acids and the diseases with which these acids are associated.

Modification of LCAT activity and HDL structure. New links between cigarette smoke and coronary heart disease risk

The mechanism(s) through which smoking influences the progression of atherosclerosis is poorly understood. Recent evidence suggests that oxidants present in the gas phase of cigarette smoke are involved. We exposed human plasma to the filtered gas phase of cigarette smoke to assess its effects on plasma components involved in the antiatherogenic reverse cholesterol transport pathway. In our model, freshly isolated plasma (24 mL) was exposed to filtered air or gas-phase cigarette smoke for up to 6 hours at 37 degrees C. Lecithin-cholesterol acyltransferase (LCAT) activity was dramatically inhibited by cigarette smoke. A single 15-minute exposure to the smoke from an eighth of a cigarette was sufficient to reduce LCAT activity by 7%; additional exposures resulted in further decreases in activity. At 6 hours, only 22% of control LCAT activity remained in plasma exposed to smoke. Compared with control, gas-phase cigarette smoke-exposed plasma possessed high-density lipoprotein (HDL) with increased (16%) negative charge and with cross-linked apolipoproteins AI and AII. These data demonstrate that gas-phase cigarette smoke can inhibit a key enzyme (LCAT) and modify an integral lipid transport particle (HDL) that are essential components for the normal function of the reverse cholesterol transport pathway. Gas-phase cigarette smoke-induced modification of the reverse cholesterol transport pathway may provide a new mechanistic link between cigarette smoke and coronary heart disease risk.

Indicators of long chain polyunsaturated fatty acid status of exclusively breastfed infants at delivery and after 20-22 days

The fatty acid composition of plasma cholesterol esters (CE), erythrocytes (RBC) and mature milk from seven lactating/women and their exclusively breastfed newborns, living on Dominica, were studied. Blood samples were taken from umbilical cord and mother at birth. A sample of breastmilk was collected on day 20-22 postpartum, together with a blood sample from the baby. At birth, cord blood plasma CE and RBC total long chain polyunsaturated fatty acid (LC-PUFA) contents were higher, and linoleic (18:2c, omega 6) and alpha-linolenic (18:3c, omega 3) acid contents lower, than in corresponding maternal compartments. Cord blood RBC LC-PUFA omega 3 content was lower and LC-PUFA omega 6 content higher than in maternal RBC. After birth, feeding with human milk led to a drop in LC-PUFA content in the plasma CE fraction, whereas RBC LC-PUFA content remained virtually constant. Current understanding of the origin and relative affinity of fatty acids incorporated in plasma CE and RBC suggests that RBC LC-PUFA content is a more reliable parameter for LC-PUFA status than plasma CE LC-PUFA content. The RBC LC-PUFA data suggest therefore that at birth the newborn has a lower LC-PUFA omega 3 status than the mother, and that this does not change during three weeks of exclusive breastfeeding.

Optimized determination of malondialdehyde in plasma lipid extracts using 1,3-diethyl-2-thiobarbituric acid: influence of detection method and relations with lipids and fatty acids in plasma from healthy adults

We investigated the influence of different concentrations of Fe3+, phosphoric acid, butylated hydroxytoluene and glutathione on the production of the malondialdehyde-1,3-diethyl-2-thiobarbituric acid adduct in plasma lipid extracts. Following organic solvent extraction the stable product was analyzed by spectrophotometry (537 nm), fluorometry (547 nm) and high-performance liquid chromatography with fluorometric detection. Using optimized reaction conditions there was good agreement between the three methods, with slightly higher values for the spectrophotometric method. Plasma total lipid malondialdehyde reference values for 24 healthy adults amounted to 1.30 +/- 0.23 mumol/l (spectrophotometric method) and 1.11 +/- 0.31 mumol/l (fluorometric method). Plasma lipid malondialdehyde concentrations correlated significantly with plasma triglycerides (r = 0.527), total cholesterol (r = 0.612) and total fatty acids (r = 0.810) and with the total number of double bonds present in plasma fatty acids with three or more double bonds (r = 0.923).

Long-term effects of linoleic-acid-enriched diet on albuminuria and lipid levels in type 1 (insulin-dependent) diabetic patients with elevated urinary albumin excretion

We conducted a 2-year prospective randomised study to investigate the effects of a linoleic-acid-enriched diet on albuminuria and lipid levels in Type 1 (insulin-dependent) diabetic patients with elevated urinary albumin excretion (overnight urinary albumin excretion rate between 10 and 200 micrograms/min). Thirty-eight patients were randomly assigned to increase dietary polyunsaturated:saturated fatty acids ratio to 1.0 by replacement of saturated fat with linoleic-acid-rich products (n = 18, two dropouts, analysis was performed in n = 16) or to continue their usual diet (n = 20). The total fat and protein content of the diet was unaltered. Clinical characteristics, albuminuria, blood pressure, glomerular filtration rate, metabolic control and dietary composition were similar in the two groups at baseline. In the high linoleic acid diet group, linoleic intake rose from 7 +/- 4 to 11 +/- 2 energy % and polyunsaturated:saturated fatty acids ratio rose from 0.60 +/- 0.28 to 0.96 +/- 0.16 (p less than 0.001 compared to usual diet group). The median increase albuminuria was 58% (95% confidence interval, 13 to 109) during the first year (p less than 0.02) and 55% (95% confidence interval, 11 to 127) (p less than 0.01) during the second year. Glomerular filtration rate remained unaltered and filtration fraction tended to rise (p less than 0.05 compared to usual diet group). In the usual diet group, albuminuria did not significantly increased by 16% (95% confidence interval, -17 to 38) and glomerular filtration rate declined during the second year. Blood pressure tended to rise similarly in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of fish oil supplementation in rheumatoid arthritis

Sixteen patients with rheumatoid arthritis entered a trial to determine the clinical and biochemical effects of dietary supplementation with fractionated fish oil fatty acids. A randomised, double blind, placebo controlled crossover design with 12 week treatment periods was used. Treatment with non-steroidal anti-inflammatory drugs and with disease modifying drugs was continued throughout the study. Placebo consisted of fractionated coconut oil. The following results favoured fish oil rather than placebo: joint swelling index and duration of early morning stiffness. Other clinical indices improved but did not reach statistical significance. During fish oil supplementation relative amounts of eicosapentaenoic acid and docosahexaenoic acid in the plasma cholesterol ester and neutrophil membrane phospholipid fractions increased, mainly at the expense of the omega-6 fatty acids. The mean neutrophil leucotriene B4 production in vitro showed a reduction after 12 weeks of fish oil supplementation. Leucotriene B5 production, which could not be detected either in the control or in the placebo period, rose to substantial quantities during fish oil treatment. This study shows that dietary fish oil supplementation is effective in suppressing clinical symptoms of rheumatoid arthritis.

Profiling of plasma cholesterol ester and triglyceride fatty acids as their methyl esters by capillary gas chromatography, preceded by a rapid aminopropyl-silica column chromatographic separation of lipid classes

A rapid procedure for the isolation of plasma cholesterol ester and triglyceride fractions with aminopropyl-silica columns, followed by analysis of their fatty acid compositions by capillary gas chromatography with flame ionization detection, is described. Within-series and long-term (six months) series-to-series precision were investigated. The isolation procedure caused minimal cross-over between the two lipid classes. Reference values for 57 apparently healthy Dutch adults were established and compared with data reported from other countries. Feeding of rats with four diets differing in their fatty acid compositions showed the relationship between the composition of the fatty acids in the diet and those esterified to cholesterol in plasma. The method is of potential usefulness to the establishment of the compliance of dietary interventions and basic dietary experiments.

Simultaneous capillary gas chromatographic profiling of medium-and long-chain fatty acid methyl esters with split injection. Correction for injection-related discrimination by the 'bracketing' method

Split injection-related discrimination can be a source of inaccuracy and imprecision in quantitative capillary gas chromatographic profiling methods for compounds with relatively big differences in boiling points, such as the methyl esters of medium- and long-chain fatty acids prepared from biological materials. We systematically investigated a standard containing equal masses of saturated fatty acid methyl esters, with chain lengths from C5 to C26, under different injection conditions, including injection temperature, sample volume and split ratio. Day-to-day performance was studied under one set of conditions. Normalized peak areas, reciprocal response factors, using either C17 or C23 as an internal standard, and 'bracketed' reciprocal response factors (peak area of each analyte divided by half the sum of the peak areas of two adjacent esters were calculated. In all experiments the bracketed reciprocal response factors were found to be closest to unity with the lowest coefficients of variation.

Rapid method for the analysis of red blood cell fatty acids by reversed-phase high-performance liquid chromatography

A high-performance liquid chromatographic method was developed for a rapid qualitative and quantitative analysis of p-bromophenacyl esters of red blood cell fatty acids in humans. Both free and bound fatty acids, extracted with hexane-2-propanol (3:2) from packed red blood cells were derivatized with p-bromophenacyl bromide and analysed. Ten identical samples taken from a mixed pool of packed red blood cells from healthy subjects were analysed on two different columns. The fatty acid p-bromophenacyl esters were analysed on a 10 RP-18 column with methanol-acetonitrile-0.01 M ammonium formate as mobile phase and also on a 10 RP-8 column with acetonitrile-0.01 M ammonium formate as mobile phase. The two methods gave analogous results except in total analysis time: that on a 10 RP-8 column is ca. 40% shorter. Furthermore, a quantitative analysis of a standard solution to evaluate the extraction procedure in the absence or in the presence of the red blood cell core indicated a significant difference when the core is present.

Effects of short-term high dose intake of evening primrose oil on plasma and cellular fatty acid compositions, alpha-tocopherol levels, and erythropoiesis in normal and type 1 (insulin-dependent) diabetic men

In addition to their usual diet, nine Type 1 (insulin-dependent) diabetic men and ten male control subjects took 20 g d, alpha-tocopheryl acetate enriched evening primrose oil (14.45 g 18:2c,omega 6, 1.73 g 18:3c,omega 6, 400 mg d,alpha-tocopheryl acetate) daily for one week. At start, diabetic patients had more 14:0, 15:0 and 18:2c,omega 6, and less 16:0, 16:1c,omega 7, 18:1c,omega 7, 18:3c,omega 6, 20:3c,omega 9, 20:3c,omega 6, 20:4c,omega 6 and 22:6c,omega 3 in plasma, erythrocytes and/or platelets. Furthermore, they had lower 16:1c,omega 7/16:0, 18:1c,omega 7/16:0, and 20:4c,omega 6/20:3c,omega 6 ratios and a higher 20:3c,omega 6/18:3c,omega 6 ratio. In diabetic patients, alpha-tocopherol levels in erythrocytes were lower, whereas those in plasma were normal. In both groups, oil intake changed fatty acid profiles. Most markedly, 20:3c,omega 6 increased, whereas the ratios 20:3c,omega 6/18:3c,omega 6 and 20:4c,omega 6/20:3c,omega 6 decreased. 20:4c,omega 6 increased in control subjects, but not in diabetic patients. Erythrocytes and platelets responded differently in their fatty acid profiles. alpha-tocopherol rose in plasma and, although less for diabetic patients, in erythrocytes. In diabetic patients as well as in control subjects, erythrocyte count, haemoglobin level, mean corpuscular haemoglobin content and concentration increased and glycosylated haemoglobin percentage decreased without an apparent decline in blood glucose levels. Plasma beta-thromboglobulin and platelet factor 4 decreased, especially in diabetic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebrotendinous xanthomatosis: a review of biochemical findings of the patient population in The Netherlands

This study gives a review of the results obtained from biochemical investigations of 20 patients in The Netherlands suffering from cerebrotendinous xanthomatosis, an inborn error of metabolism in bile acid synthesis. Diagnosis can best be established by determining the excretion of urinary bile alcohols, in particular 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha,23,25-pentol, in urine by means of capillary gas chromatography. Measurement of serum cholestanol levels or serum cholestanol/cholesterol ratios, commonly used for establishing cerebrotendinous xanthomatosis, are not reliable. The effectiveness of the different therapies, i.e. administration of bile acids, can be evaluated by monitoring the urinary excretion of bile alcohols. From such investigations it was concluded that cholic acid especially, but also chenodeoxycholic acid are the therapies of choice for the treatment of cerebrotendinous xanthomatosis. All patients, until now diagnosed in The Netherlands were not discovered before the third or fourth decade of life because the characteristic signs only then become manifest clearly. Unfortunately, because sterol storage is almost irreversible, therapy only results in minor improvements of the patient's condition. Therefore early detection of the presence of cerebrotendinous xanthomatosis is desirable so that treatment can start before extensive storage of sterols is a fact. We developed some laboratory assays with the purpose of early detection. One consists of the detection of cerebrotendinous xanthomatosis carriers by subjecting them to oral cholestyramine administration and monitoring the urinary excretion of the bile alcohol 5 beta-cholestane-3 alpha,7 alpha,12 alpha,23,25-pentol before and after treatment. Secondly, a relatively simple screening test for cerebrotendinous xanthomatosis was developed based on an enzymatic assay of 7 alpha-hydroxylated steroids in urine. After suitable modification this assay in principle allows the screening of large populations for the existence of cerebrotendinous xanthomatosis and thus to detect the disease at an earlier stage of life.

Influence of docosahexaenoic acid in vitro on intracellular adriamycin concentration in lymphocytes and human adriamycin-sensitive and -resistant small-cell lung cancer cell lines, and on cytotoxicity in the tumor cell lines

An increase in the therapeutic effects of cancer chemotherapeutic agents and circumvention of drug resistance in cancer cells might result from an increase in the intracellular drug level. Alteration of the lipid domain of the cell membrane can result in a higher intracellular drug level. This alteration was achieved in human lymphocytes and in human adriamycin (ADR)-sensitive and -resistant small-cell lung carcinoma cells in vitro by incubation with docosahexaenoic acid (22:6). Incorporation of the fatty acid in cellular phospholipids was measured by gas chromatographic analysis. A significant increase of 22:6 could be reached without loss of viability in all 3 cell types. Incorporation was demonstrated notably in the phosphatidyl choline, phosphatidyl ethanolamine and phosphatidylserine, and was most pronounced in the phosphatidyl choline of the ADR-resistant line. After a 1-hr incubation with ADR, a 10-30% increase in intracellular adriamycin concentration was found in all 3 cell types previously incubated for 4 days with 22:6. After 1 hr incubation with ADR there was no increase in cytotoxicity in the sensitive cell line when measured by soft agar clonogenic assay and a partial reversal (52 to 14) of resistance factor (ratio of drug doses to produce 50% growth inhibition) in the resistant cell line. Increasing the time of ADR exposure from 1 to 4 hr further reduced the resistance factor to 8.6.