Relationship between fat cell size and number and fatty acid composition in adipose tissue from different fat depots in overweight/obese humans

OBJECTIVE: To evaluate the body fat distribution and fat cell size and number in an overweight/obese population from both genders, and to determine the possible relationship between fat cell data from three different adipose tissue localizations (subcutaneous (SA), perivisceral and omental) and adipose tissue composition and dietary fatty acid. DESIGN: The sample consisted of 84 overweight/obese patients (29 men and 55 women) who have undergone abdominal surgery. The adipocyte size and total fat cell number was studied. Fat cell data were related with anthropometric, adipose tissue and subject's habitual diet fatty acid composition. MEASUREMENTS: Fat cell size was measured according to a Sj?str?m method from the three adipose depots. Total fat cell number was also calculated. The fatty acid composition of adipose tissue was examined by gas chromatography. The subjects diet was studied by a 7 days dietary record. RESULTS: Our data showed a negative relationship between the adipocyte size and the n-6 and n-3 fatty acids content of the SA adipose tissue (r=-0.286, P=0,040; r=-0.300, P=0.030) respectively, and the n-6 in the omental depots (r=-0.407, P=0.049) in the total population. Positive associations with the total of saturated (r=0.357, P=0.045) and negative (r=-0.544, P=0.001) with the n-9 fatty acids were observed when the relationship between the adipocyte number and the fatty acid composition of the different anatomical fat regions was studied. Dietary fatty acids composition positively correlated with fat cell size for the myristic acid (14:0) in men in the visceral depot (r=0.822, P=0.023), and for the saturated fatty acids (SFAs) in women in the omental depot (r=0.486, P=0.035). CONCLUSION: In the present study, for the first time in humans we found that n-3 and n-6 fatty acids are related to a reduced adipocyte size according to the depot localization. In contrast, adipose tissue and dietary SFAs significantly correlated with an increase in fat cell size and number. No significant associations were found between n-9 acids content and adipocyte size. However, n-9 adipose tissue fatty acids content was inversely associated with fat cell number showing that this type of fatty acid could limit hyperplasia in obese populations. The differences observed in the three different regions, perivisceral, omental and SA fat, indicate that this population adipose tissue have depot-specific differences.     

Fatty acid composition of adipose tissue and serum micronutrients in relation to common rheumatic complaints in Swedish adults 50-70 years old.

Biochemical markers of nutritional status, such as adipose tissue fatty acid composition and circulating levels of micronutrients, may reflect dietary habits, but may also be related to inflammatory activity. We examined the relationship between common rheumatic complaints such as osteo-arthrosis, arthralgia, tendinitis, low-back pain, and neck pain, and the composition of adipose tissue fatty acids, serum concentrations of retinol, ascorbic acid, alpha-tocopherol and selenium in 502, out of 900 randomly selected individuals 50-70 years old. Compared with control subjects the rheumatic group as a whole (p less than 0.01) as well as subgroups like those with arthralgia (p less than 0.01), subacromial shoulder pain (p less than 0.03), and low-back pain (p less than 0.05), had decreased proportions of adipose tissue arachidonic acid. The abnormalities correlated with the duration of the symptom-free period preceding adipose tissue sampling and could not be explained by the evaluation of possible confounding factors. Regarding other fatty acids and micronutrients there were no differences between symptomatic subjects and controls. One explanation for the low proportion of adipose tissue arachidonic acid may be increased eicosanoid production.     

Fatty acid compositions of lipids in mesenteric adipose tissue and lymphoid cells in patients with and without Crohn's disease and their therapeutic implications

BACKGROUND: The physiological bases for roles of adipose tissue and fatty acids in the symptoms and dietary treatments of Crohn's disease (CD) are poorly understood. The hypothesis developed from experiments on rodents that perinodal adipocytes are specialized to provision adjacent lymphoid tissues was tested by comparing the composition of triacylglycerol and phospholipid fatty acids in homologous samples of mesenteric adipose tissue and lymph nodes from patients with or without CD. METHODS: Mesenteric perinodal and other adipose tissue and lymph nodes were collected during elective surgery for CD and other conditions. Fatty acids were extracted, identified, and quantified by thin-layer and gas-liquid chromatography. RESULTS: Perinodal adipose tissue contained more unsaturated fatty acids than other adipose tissue in controls, as reported for other mammals, but site-specific differences were absent in CD. Lipids from adipose and lymphoid tissues had more saturated fatty acids but fewer polyunsaturates in patients with CD than controls. In adipose tissue samples, depletion of n-3 polyunsaturates was greatest, but n-6 polyunsaturates, particularly arachidonic acid, were preferentially reduced in lymphoid cells. Ratios of n-6/n-3 polyunsaturates were higher in adipose tissue but lower in lymphoid cells in patients with CD than in controls. CONCLUSIONS: Site-specific differences in fatty acid composition in normal human mesentery are consistent with local interactions between lymph node lymphoid cells and adjacent adipose tissue. These site-specific properties are absent in CD, causing anomalies in composition of lymphoid cell fatty acids, which may explain the efficacy of elemental diets containing oils rich in n-6 polyunsaturates.     

Dietary N-3 polyunsaturated fatty acids decrease biliary cholesterol saturation in gallstone disease.

Because fatty acid composition of biliary phospholipids influences cholesterol secretion into bile, we investigated whether replacement of n-1 monounsaturated or n-6 polyunsaturated fatty acids with n-3 polyunsaturated fatty acids in biliary phosphatidylcholines reduces supersaturation with cholesterol and prevents precipitation of cholesterol crystals in bile of gallstone patients. Seven patients with radiolucent gallstones in functioning gallbladders were studied before (control) and after 5 wk of dietary supplementation with marine fish oil (11.3 gm/day = 3.75 gm n-3 polyunsaturated fatty acids/day). Duodenal bile was collected for analysis during intravenous infusion of cholecystokinin. Gallbladder emptying in response to cholecystokinin was comparable before and during intake of n-3 polyunsaturated fatty acids. Intake of n-3 polyunsaturated fatty acids increased (p less than 0.001) the fractions of eicosapentaenoic and docosahexaenoic acids and decreased the fractions of linoleic (p less than 0.001) and arachidonic acids (p less than 0.02) in biliary phospholipids. Concomitantly, the molar ratio of cholesterol to phospholipids decreased (-19%; p less than 0.05). As a consequence, the cholesterol saturation index was reduced by -25% (p = 0.01), from 1.60 +/- 0.44 to 1.24 +/- 0.38. However, in vitro nucleation time of duodenal bile was not prolonged. The decrease in cholesterol saturation was not sufficient to prevent nucleation of cholesterol crystals in bile of gallstone patients. In conclusion, our data suggest that cholesterol saturation can be influenced by the fatty acid composition of the phosphatidylcholines secreted in bile.     

Selective mobilisation of fatty acids from human adipose tissue

Background: Adipose tissue is a storage organ for dietary fat. During fasting, fatty acids are released into serum as free fatty acids (FFA). Experimental studies indicate that fatty acids are selectively mobilised from adipose tissue into serum. The aim of this study was to investigate whether the composition of the serum FFA fraction reflects selective mobilisation in the fasting state in humans. Methods: The fatty acid composition of fasting serum FFA and adipose tissue were analysed from 112 patients with myocardial infarction and 107 healthy control subjects using gas-liquid chromatography. The subjects' habitual diet was analysed using a food-frequency questionnaire. Results: Significant correlations were found between serum FFA and adipose tissue, particularly for the percentage content of linoleic acid (r=0.73), eicosapentaenoic acid (r=0.68), alpha-linolenic acid (r=0.67) and palmitoleic acid (r=0.60). Percentage contents of palmitic, stearic, linoleic, alpha-linolenic, eicosapentaenoic and docosahexaenoic acid were higher in serum FFA than in adipose tissue, whereas oleic and palmitoleic acid were relatively more abundant in adipose tissue. This may indicate that the former group of fatty acids is preferentially mobilised from adipose tissue into serum. High correlations for polyunsaturated fatty acids were observed between percentage contents of dietary and adipose tissue fatty acids. The correlation of fatty acids between diet and serum FFA was weak, but a tendency towards higher correlations for polyunsaturated fatty acids was observed. Conclusions: Our findings are compatible with the hypothesis that, in the fasting state, fatty acids are selectively mobilised from adipose tissue into serum FFA.     

Fat intake and fatty acid profile in plasma phospholipids and adipose tissue in patients with Crohn's disease, compared with controls

OBJECTIVES: Fatty acid metabolism is involved in the immune response and inflammation processes in patients with Crohn's disease (CD). Fatty acid changes may be relevant to the clinical course of the disease. The aim of this study was to compare the qualitative and quantitative fat intake and fatty acid composition of plasma phospholipids and adipose tissue in a defined population of CD patients with those in matched controls. METHODS: Dietary fat intake and fatty acid profile of plasma phospholipids and adipose tissue were assessed in two patient populations: 20 patients with recently diagnosed CD and 32 patients with longstanding (> 10 yr) CD clinically in remission, matched for age and gender with healthy controls. RESULTS: We observed no significant differences in quantitative or qualitative fat intake between CD patients and controls. Percentages of linoleic acid and alpha-linolenic acid in plasma phospholipids or adipose tissue were not significantly different between patients and controls. However, we observed a significantly (p < 0.05) lower percentage of the sum of the n-3 fatty acids, with significantly (p < 0.01) higher levels of clupanodonic acid (22:5n-3) and significantly (p < 0.05) lower levels of docosahexaenoic (22:6n-3) and arachidonic acid (20:4n-6). The aberrant fatty acid profile was more evident in patients with longstanding CD than in patients with recently diagnosed CD. CONCLUSION: The aberrant fatty acid profile found in these CD patients is a result of altered metabolism rather than of essential fatty acid malabsorption. The reported findings may be important in the pathophysiology of CD and hence in the choice of fatty acids to be used when therapeutic supplementation is considered in CD patients.     

Non-invasive determination of cardiac output: comparison of a novel CW Doppler ultrasonic technique and inert gas rebreathing

Marine n-3 polyunsaturated fatty acids (n-3 PUFAs) in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may reduce the risk of coronary heart disease (CHD) and have anti-inflammatory effects. We examined whether levels of serum adiponectin were related to the occurrence and extent of CHD, and whether intake of n-3 PUFAs was associated to high levels of adiponectin. Serum adiponectin and the content of n-3 PUFAs in subcutaneous adipose tissue, platelets and granulocytes were measured in 291 patients referred to elective coronary angiography. Significantly lower levels of serum adiponectin were observed in patients with coronary stenoses compared to patients without stenoses (7336+/-3598 ng/ml vs 10,203+/-8396 ng/ml; p=0.003), but no significant correlation was seen between serum adiponectin and the extent of CHD. In men, serum adiponectin correlated to levels of the content of EPA in platelets (r=0.26; p<0.01) and in granulocytes (r=0.23; p<0.01) and to the content of DHA in subcutaneous adipose tissue (r=0.15; p<0.05) and granulocytes (r=0.17; p<0.05). After regression analysis EPA in platelets (p=0.017) and granulocytes (p=0.030) remained an independent correlate of adiponectin levels, while DHA was no longer an independent correlate. In conclusion, serum levels of adiponectin were lower in patients with angiographically documented coronary artery disease. Also, intake of EPA may increase serum adiponectin and through this exert a protective effect on CHD.     

Arachidonic acid and early human growth: is there a relation?

Growth failure is a classical sign of essential fatty acid deficiency. We investigated whether birth weight correlates with the postnatal essential fatty acid status in a group of 29 premature infants. A significant and positive correlation between body weight and plasma triglyceride content of arachidonic acid (20:4n-6) (r = 0.47, p = 0.01) and total omega-6 long-chain polyunsaturated fatty acids (r = 0.49, p less than 0.01) was found. In contrast, there was no positive relation to linoleic acid (18:2n-6) or any omega-3 fatty acid but a significant inverse correlation to alpha-linolenic acid (18:3n-3). We propose that during early life arachidonic acid may have a growth-promoting effect which could be related to its role as an eicosanoid precursor or to its structural function in membrane lipids.     

Adipose fatty acid composition and the risk of serious ventricular arrhythmias in acute myocardial infarction

The relation between subcutaneous adipose tissue fatty acid composition and serious ventricular arrhythmias during acute myocardial infarction was studied in 2 groups of patients. In group 1 (n = 42), studied retrospectively, patients with ventricular fibrillation or tachycardia had a higher concentration of long-chain saturated fatty acids than those without (32.5 +/- 0.8% vs 29.7 +/- 0.4% [mean +/- standard error of the mean], p less than 0.01). In a prospective study, patients with arrhythmias (n = 106) had higher levels of long-chain saturated fatty acids (32.1 +/- 0.5% vs 30.7 +/- 0.4%, p less than 0.05) and of stearic acid (4.9 +/- 0.2% vs 4.4 +/- 0.1%, p less than 0.02) and a lower concentration of palmitoleic acid (7.3 +/- 0.3% vs 8.1 +/- 0.2%, p less than 0.005). When peak plasma creatine kinase concentrations were included with the individual fatty acid levels in a multiple logistic regression, only creatine kinase correlated significantly with ventricular arrhythmias (p less than 0.01). Thus, saturated fatty acids in cardiac membranes may lead to greater vulnerability to ventricular arrhythmias, although infarct size is the only statistically significant predictor after multiple regression analysis.     

Effects of long-chain monounsaturated and n-3 fatty acids on fatty acid oxidation and lipid composition in rats

Long-chain n-3 fatty acids and fat fish are reported, among multiple physiological properties, to enhance peroxisomal beta-oxidation and effect triacylglycerol status. Long-chain n-3 and monounsaturated fatty acids are the main portion of fatty acids in fat fish. The individual effect of long-chain monounsaturated fatty acids on beta-oxidation and fatty acid composition was tested and compared to the effect of n-3 polyunsaturated and saturated fatty acids in a 3-week feeding experiment of rats. To explore the contribution from long-chain monounsaturated fatty acids in these aspects, the effect of long-chain n-3 and monounsaturated fatty acids on mitochondrial and peroxisomal beta-oxidation was compared, as well as fatty acid composition of adipose tissue, liver and serum. Fatty acid oxidase, palmitoyltransferase I and II activities, the amount of serum lipids, and the fatty acid composition of lipid fractions from the organs were analysed. The peroxisomal beta-oxidation was enhanced by the n-3 fatty acids, whereas a small, significant increase with the monounsaturated fatty acids was observed. There was a stimulation of the mitochondrial oxidation with the n-3 fatty acids, but monounsaturated fatty acids gave a small, nonsignificant decrease. With n-3 fatty acids there was a considerable decrease in the levels of serum triacylglycerol, phospholipids, free fatty acids and total cholesterol, while there were only minor effects of monounsaturated fatty acids. As judged from the fatty acid composition data, there was a mobilization on n-3 fatty acids from the adipose tissue to liver and plasma with the n-3 diet. This observation was also seen with the monounsaturated fatty acid-enriched diet. In conclusion, monounsaturated fatty acids seemed to stimulate peroxisomal beta-oxidation and to increase plasma triacylglycerol, whereas the mitochondrial oxidation was slightly decreased.     

Site dependency of fatty acid composition in adipose triacylglycerol in rats and its absence as a result of high-fat feeding

It is currently believed that metabolic syndrome, in general, and type 2 diabetes mellitus, in particular, depend more on visceral than on subcutaneous adipose tissue. However, the relationship between insulin resistance and fatty acid composition in visceral and subcutaneous adipose tissues remains to be clarified. In the present study, we extracted the triacylglycerol from visceral (epididymis and mesentery) and subcutaneous adipose tissues in normal and insulin-resistant, high-fat-fed (HFF) rats and determined the composition of each fatty acid. The concentrations of palmitoleic, docosapentaenoic, docosahexaenoic, dihomo-γ-linolenic, arachidonic, and docosatetraenoic acids were higher in epididymal adipose tissue than in mesenteric and subcutaneous adipose tissues; but no significant differences were detected between mesenteric and subcutaneous tissues in the normal group or among all the sites in the HFF rats. In the HFF group, stearic and oleic acid concentrations were higher, whereas n-3 and n-6 polyunsaturated ones were lower, than those in the normal group. Palmitoleic acid and some n-3 and n-6 polyunsaturated fatty acid compositions in adipose tissue triacylglycerol depend on anatomical location, which may affect the properties and/or function of adipose tissues. These results at least in part suggest that the properties of adipose tissue are difficult to distinguish based only on their "visceral" or "subcutaneous" sites. In addition, the absence of site dependence and/or difference in balance among saturated, monounsaturated, and polyunsaturated fatty acids may play an important role in the development of insulin resistance in the HFF rats.     

Adipose tissue fatty acids in Scottish men and women: results from the Scottish Heart Health Study.

The fatty acid composition of adipose tissue from 4114 men and women across 22 districts of Scotland is described. A biopsy of subcutaneous adipose tissue was obtained from the upper arm using a skin biopsy punch. Overall the proportion of saturated fatty acids was lower in women and those of monounsaturated and polyunsaturated higher than in men. There were significant effects of age on adipose tissue fatty acid composition, particularly in women, where the proportion of saturated fatty acids decreased and that of monounsaturated fatty acids increased with advancing age. The fatty acid composition of adipose tissue varied among the districts studied. The district standardised mortality ratio for coronary heart disease was positively correlated with the district mean oleic acid value and inversely correlated with the district mean linoleic acid value. This paper supports the importance of adipose tissue fatty acids as indicators of risk factor status for coronary heart disease.     

The impact of dietary fat composition on serum leptin concentrations in healthy nonobese men and women

The recently discovered hormone leptin is primarily secreted by adipose tissue and serves as an internal signal indicating the size of body fat stores. The aim of the present study was to investigate the impact of the dietary fatty acid composition on serum leptin concentrations. Therefore, serum leptin levels were measured by RIA in healthy nonobese men (n = 30) and women (n = 25). First, all participants received a baseline high-fat diet, rich in saturated fat, for 2 wk and were then randomly assigned to one of three high-fat dietary treatments, which contained refined olive oil (rich in monounsaturated fatty acids, n = 19), rapeseed oil [rich in monounsaturated fatty acids and alpha-linolenic acid (18:3n-3), n = 17], or sunflower oil (rich in n-6-polyunsaturated fatty acids, n = 19) as the principal source of fat for 4 wk. On the rapeseed oil diet, serum leptin concentrations increased slightly in men [+0.25 ng/ml, T(9) = -2.778, P = 0.021], but decreased distinctly in women [-4.70 ng/ml, T(6) = 5.083, P = 0.002]. Both the olive oil and the sunflower oil diet did not affect serum leptin concentrations. Thus, it is proposed that serum leptin levels were affected by the high amount of alpha-linolenic acid in rapeseed oil. However, questions remain as to why this diet differently affected serum leptin in men and women.     

Lipoprotein-associated phospholipase A2 concentrations in plasma are associated with the extent of coronary artery disease and correlate to adipose tissue levels of marine n-3 fatty acids

Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is an emerging risk factor for cardiovascular disease. In the present study, plasma levels of Lp-PLA(2) were measured in patients (n=301) admitted to elective coronary angiography because of suspected coronary artery disease (CAD). In a multiple linear regression analysis, the degree of CAD (0-, 1-, 2- or 3-vessel disease) and plasma LDL cholesterol significantly correlated to Lp-PLA(2) levels. Also the content of the marine n-3 fatty acid, eicosapentaenoic acid (EPA) in adipose tissue, a measure of long-term intake of seafood independently and inversely (r=-0.18, p<0.01) correlated with plasma levels of Lp-PLA(2). The results support the view that Lp-PLA(2) may relate to CAD and that intake of marine n-3 fatty acids might reduce plasma Lp-PLA(2) suggesting another mechanism by which n-3 fatty acids could reduce the risk of cardiovascular disease.     

Changes in the Fatty Acid Profile of Plasma and Adipose Tissue in Rats after Long-Term Ethanol Feeding

The effect of chronic ethanol feeding on the fatty acid composition of plasma and abdominal adipose tissue in rats was studied. Animals were maintained on a 30% ethanol solution in drinking water for 3 and 5 months. Control rats were given water. Caloric intake was similar in control and ethanol-fed rats at the end of the experimental period. However, a decrease in body weight was observed in rats that had consumed ethanol. Palmitoleic (16:1n7) and oleic (18:1n9) acids increased markedly, and linoleic acid (18:2n6) decreased in the plasma and in the adipose tissue of ethanol-fed rats with respect to control rats. After 3 months of ethanol ingestion, long-chain polyunsaturated fatty acids were reduced both in plasma and adipose tissue. When ethanol was administered for 5 months, only plasma long-chain polyunsaturated fatty acids of the n-3 series were decreased. This suggest that changes induced by ethanol ingestion in essential fatty acid metabolism is less pronounced when ethanol feeding is maintained for a long period of time.     

Physical training and adipose tissue fatty acid composition in men

Four months physical training significantly raised the mean proportions (%) of lauric (+0.64), myristic (+0.52), stearic (+2.06) and linoleic (+1.69) acids and lowered the mean proportions of palmitic (?1.46) and oleic (?3.46) acids in adipose tissue of 20 apparently normal men aged 20–55 yr. These changes were dependent on pretraining proportions of the fatty acids. In addition, the decreases in palmitic acid and oleic acid proportions were positively correlated (? = 0.905, P < 0.01, τ = 0.758, P < 0.01). The pattern of significant correlations among adipose tissue fatty acids was altered as a result of training. We suggest that preferential mobilisation of fatty acids from adipose tissue is responsible for the change in adipose tissue fatty acid composition with increased physical training. The significant increase in adipose tissue linoleic acid proportions may be linked with the reduced risk of coronary heart disease which has been previously associated with increased physical activity.     

Functional expression of a Delta12 fatty acid desaturase gene from spinach in transgenic pigs

Linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3) are polyunsaturated fatty acids that are essential for mammalian nutrition, because mammals lack the desaturases required for synthesis of Delta12 (n-6) and n-3 fatty acids. Many plants can synthesize these fatty acids and, therefore, to examine the effects of a plant desaturase in mammals, we generated transgenic pigs that carried the fatty acid desaturation 2 gene for a Delta12 fatty acid desaturase from spinach. Levels of linoleic acid (18:2n-6) in adipocytes that had differentiated in vitro from cells derived from the transgenic pigs were approximately 10 times higher than those from wild-type pigs. In addition, the white adipose tissue of transgenic pigs contained approximately 20% more linoleic acid (18:2n-6) than that of wild-type pigs. These results demonstrate the functional expression of a plant gene for a fatty acid desaturase in mammals, opening up the possibility of modifying the fatty acid composition of products from domestic animals by transgenic technology, using plant genes for fatty acid desaturases.     

Lecithin : cholesterol acyl transfer (LACT) and fatty acid composition of lecithin and cholesterol esters in young male myocardial infarction survivors.

Lecithin : cholesterol acyl transfer (LCAT) and relative fatty acid composition of serum lecithin and cholesterol esters were studied in 20 young male survivors of myocardial infarction (MI). Comparisons were made with controls matched for serum cholesterol. There was no difference in LCAT rate between MI patients and controls. The relative content of arachidonic acid in cholesterol esters was higher in MI patients. The fatty acid composition of lecithin and cholesterol esters suggests an equal transfer of linoleic and oleic acids from lecithin to cholesterol. Furthermore negative correlations were found between LCAT and linoleic acid content of lecithin (r = --0.43, P less than 0.01) and cholesterol esters (r = --0.45, P less than 0.01). This inverse relationship does not seem to be linked to substrate specificity, but rather to be mediated by influences in common on serum lipid content and turnover.     

Preeclampsia is associated with compromised maternal synthesis of long-chain polyunsaturated Fatty acids, leading to offspring deficiency

Obesity and excessive lipolysis are implicated in preeclampsia (PE). Intrauterine growth restriction is associated with low maternal body mass index and decreased lipolysis. Our aim was to assess how maternal and offspring fatty acid metabolism is altered in mothers in the third trimester of pregnancy with PE (n=62) or intrauterine growth restriction (n=23) compared with healthy pregnancies (n=164). Markers of lipid metabolism and erythrocyte fatty acid concentrations were measured. Maternal adipose tissue fatty acid composition and mRNA expression of adipose tissue fatty acid-metabolizing enzymes and placental fatty acid transporters were compared. Mothers with PE had higher plasma triglyceride (21%, P<0.001) and nonesterified fatty acid (50%, P<0.001) concentrations than controls. Concentrations of major n-6 and n-3 long-chain polyunsaturated fatty acids in erythrocytes were 23% to 60% lower (all P<0.005) in PE and intrauterine growth restriction mothers and offspring compared with controls. Subcutaneous adipose tissue Δ-5 and Δ-6 desaturase and very long-chain fatty acid elongase mRNA expression was lower in PE than controls (respectively, mean [SD] control 3.38 [2.96] versus PE 1.83 [1.91], P=0.030; 3.33 [2.25] versus 1.03 [0.96], P<0.001; 0.40 [0.81] versus 0.00 [0.00], P=0.038 expression relative to control gene [square root]). Low maternal and fetal long-chain polyunsaturated fatty acid concentrations in PE may be the result of decreased maternal synthesis.     

Erythrocyte membrane phospholipid composition as a biomarker of dietary fat

BACKGROUND/AIMS: In a cross-sectional study, we investigated the relationship between erythrocyte membrane phospholipid fatty acid composition and dietary fat; we also investigated roles of menopausal status, age, body mass index (BMI) and waist-to-hip ratio (WHR) in interindividual variation of the biomarker. METHODS: Study participants were 204 women, aged 39-65 years, drawn from the ORDET cohort and selected as controls in a study of breast cancer. Membrane composition was assessed using capillary gas chromatography. Dietary fat composition was evaluated using a food frequency questionnaire. RESULTS: In pre- and postmenopausal women, erythrocyte membrane phospholipid levels of linoleic acid, oleic acid, and mono-unsaturated fatty acids were significantly associated with corresponding dietary measures (partial correlation coefficients: 0.23 and 0.39; 0.45 and 0.47; 0.40 and 0.48; respectively, in pre- and postmenopausal women). Among postmenopausal women, membrane poly-unsaturated fatty acids were correlated with the corresponding dietary measure (r=0.39, p<0.001). Membrane eicosapentanoic and docosahexanoic acid levels were significantly correlated with intake of fish/shell fish : r=0.21 and r=0.43 (premenopausal), and r=0.41 and r=0.44 (postmenopausal). Age, BMI and WHR had independent effects on membrane lipid composition. Age was associated with delta-6 desaturase activity in postmenopausal women (r=0.25, p<0.05). BMI was negatively associated with delta-9 desaturase activity in both pre- and postmenopausal women (r=-0.29, p=0.01 and r=-0.22, p<0.01, respectively). WHR was negatively associated with delta-5 desaturase activity in pre-menopausal women (r=-024, p<0.05). CONCLUSIONS: Erythrocyte membrane levels of some specific fatty acids can be used as biomarkers of these fatty acids as proportions of dietary fat.