Lipids in Health and Disease - Latest Articles

Effects of cardiovascular lifestyle change on lipoprotein subclass profiles defined by nuclear magnetic resonance spectroscopy

David Decewicz — 2009-06-29T00:00:00Z

Background: Low-density lipoprotein (LDL) cholesterol lowering is a primary goal in clinical management of patients with cardiovascular disease, but traditional cholesterol levels may not accurately reflect the true atherogenicity of plasma lipid profiles. The size and concentration of lipoprotein particles, which transport cholesterol and triglycerides, may provide additional information for accurately assessing cardiovascular risk. This study evaluated changes in plasma lipoprotein profiles determined by nuclear magnetic resonance (NMR) spectroscopy in patients participating in a prospective, nonrandomized lifestyle modification program designed to reverse or stabilize progression of coronary artery disease (CAD) to improve our understanding of lipoprotein management in cardiac patients. Results: The lifestyle intervention was effective in producing significant changes in lipoprotein subclasses that contribute to CAD risk. There was a clear beneficial effect on the total number of LDL particles (-8.3%, p<0.05 compared to matched controls), small dense LDL particles (-9.5%, p<0.05), and LDL particle size (+0.8%; p<0.05). Likewise, participants showed significant improvement in traditional CAD risk factors such as body mass index (-9.9%, p<0.01 compared to controls), total cholesterol (-5.5%, p<0.05), physical fitness (+37.2%, p<0.01), and future risk for CAD (-7.9%, p<0.01). Men and women responded differently to the program for all clinically-relevant variables, with men deriving greater benefit in terms of lipoprotein atherogenicity. Plasma lipid and lipoprotein responses to the lifestyle change program were not confounded by lipid-lowering medications. Conclusions: In at risk patients motivated to participate, an intensive lifestyle change program can effectively alter traditional CAD risk factors and plasma lipoprotein subclasses and may reduce risk for cardiovascular events. Improvements in lipoprotein subclasses are more evident in men compared to women.

Oleic acid and peanut oil high in oleic acid reverse the inhibitory effect of insulin production of the inflammatory cytokine TNF-alpha both in vitro and in vivo systems.

Evros Vassiliou — 2009-06-26T00:00:00Z

Background: Chronic inflammation is a key player in pathogenesis. The inflammatory cytokine, tumor necrosis factor-alpha is a well known inflammatory protein, and has been a therapeutic target for the treatment of diseases such as Rheumatoid Arthritis and Crohn's Disease. Obesity is a well known risk factor for developing non-insulin dependent diabetes melitus. Adipose tissue has been shown to produce tumor necrosis factor-alpha, which has the ability to reduce insulin secretion and induce insulin resistance. Based on these observations, we sought to investigate the impact of unsaturated fatty acids such as oleic acid in the presence of TNF-alpha in terms of insulin production, the molecular mechanisms involved and the in vivo effect of a diet high in oleic acid on a mouse model of type II diabetes, KKAy. Methods: The rat pancreatic beta cell line INS-1 was used as a cell biological model since it exhibits glucose dependent insulin secretion. Insulin production assessment was carried out using enzyme linked immunosorbent assay and cAMP quantification with competitive ELISA. Viability of TNF-alpha and oleic acid treated cells was evaluated using flow cytometry. PPAR-gamma translocation was assessed using a PPRE based ELISA system. In vivo studies were carried out on adult male KKAy mice and glucose levels were measured with a glucometer. Results: Oleic acid and peanut oil high in oleic acid were able to enhance insulin production in INS-1. TNF-alpha inhibited insulin production but pre-treatment with oleic acid reversed this inhibitory effect. The viability status of INS-1 cells treated with TNF-alpha and oleic acid was not affected. Translocation of the peroxisome proliferator- activated receptor transcription factor to the nucleus was elevated in oleic acid treated cells. Finally, type II diabetic mice that were administered a high oleic acid diet derived from peanut oil, had decreased glucose levels compared to animals administered a high fat diet with no oleic acid. Conclusions: Oleic acid was found to be effective in reversing the inhibitory effect in insulin production of the inflammatory cytokine TNF-alpha. This finding is consistent with the reported therapeutic characteristics of other monounsaturated and polyunsaturated fatty acids. Furthermore, a diet high in oleic acid, which can be easily achieved through consumption of peanuts and olive oil, can have a beneficial effect in type II diabetes and ultimately reverse the negative effects of inflammatory cytokines observed in obesity and non insulin dependent diabetes mellitus.

Sex-associated effect of CETP and LPL polymorphisms on postprandial lipids in familial hypercholesterolaemia

Katherine Anagnostopoulou — 2009-06-26T00:00:00Z

Background: This study assessed the gender-specific influence of the cholesteryl ester transfer protein (TaqIB, I405V) and lipoprotein lipase (S447X) polymorphisms on the response to an oral fat tolerance test in heterozygotes for familial hypercholesterolaemia. Methods: We selected and genotyped 80 men and postmenopausal women heterozygous for familial hypercholesterolaemia (main group) as well as 11 healthy control subjects. Patients were subgrouped based on their response to oral fat tolerance test. The oral fat tolerance test was defined as pathological when postprandial triglyceride concentration was higher than the highest triglyceride concentration observed in healthy subjects (220 mg/dl) at any time (2, 4, 6 or 8 h). Results: In the pathological subgroup, men had significantly higher incremental area under the curve after oral fat tolerance test than postmenopausal women. Furthermore, multivariate analysis revealed a gender association of TaqIB and I405V influence on postprandial lipaemia in this subgroup. Conclusion: In conclusion, it seems that gender and TaqIB polymorphism of the cholesteryl ester transfer protein gene were both associated with the distribution of triglyceride values after oral fat tolerance test, only in subjects with a pathological response to oral fat tolerance test. Specifically, men carrying the B2 allele of the TaqIB polymorphism showed a higher postprandial triglyceride peak and a delayed return to basal values compared with women carrying B2. However, further investigations in larger populations are required to replicate and confirm these findings.

n-3 polyunsaturated fatty acids in milk is associate to weight gain and growth in premature infants

Sandra Barboza Tinoco — 2009-06-26T00:00:00Z

Background: Linoleic 18:2 (n-6) and alpha linolenic 18:3 (n-3) essential fatty acids and long-chain polyunsaturated fatty acids (LC-PUFA) are essential nutrients for growth and neonatal development. Consumption of preformed n-3 LC-PUFA has been shown to increase gestational duration and to decrease the incidence of premature birth in human studies. This study evaluated the association of essential fatty acids and LC-PUFA in breast milk on the growth of premature children (weight, height and head circumference).Study design: Thirty-seven premature infants with a gestational age of 37 weeks or less were followed until 6 months of gestational age, adjusted for prematurity. The milk from mothers, weight, height and head circumference measures of children were collected during the follow up. The breast milk fatty acids were quantified by gas-liquid chromatography. Results: Our results showed that total n-3 PUFA was positively associated with weight gain (p = 0.05), height (p = 0.04) and body mass index (BMI) of children (p = 0.05). Our results also indicate that both linoleic acid and total essential fatty acids were positively associated with BMI and head circumference, whereas oleic acid was positively associated only with head circumference. Conclusion: These results suggest that the n-3 PUFA composition of milk may be considered an important predictor of weight gain and growth. Considering the advantages of n-3 LC-PUFA consumption on infant growth and visual function and its association with reduced incidence of premature birth, dietitians should advise pregnant women to increase their intake of foods high in n-3 LC-PUFA.

Influence of conjugated linoleic acid on the porcine immune response and morbidity: a randomized controlled trial

Tomaz Malovrh — 2009-06-22T00:00:00Z

Background: Conjugated linoleic acid (CLA) has diverse influences on the immune response in different experimental models. In the present study we investigated the effect of CLA feeding on inflammatory and immune responses in a piglet model. We studied the duration of this effect and possible detrimental effects of CLA feeding. After 12 weeks of CLA and control supplementation and washout, animals were sacrificed and parenchymal organs were histologically examined. Results: In activated peripheral mononuclear cells interferon-gamma was significantly (p=0.008) lower in the CLA group by the end of the feeding period. This effect disappeared as soon as supplementation stopped. No differences were found in the tumour necrosis factor-alpha, interleukin-10 production, serum immunoglobulin-G levels and fat infiltration of the liver, except that fat storage cell infiltration was significantly (p<0.04) higher in the CLA-fed group. The effect of time for interferon-gamma, interleukin-10 and immunoglobulin-G levels was statistically significant. Conclusions: At the end of the feeding period the interferon-gamma response was depressed. However, the maturation of the piglet immune system in our young pig model probably outweighs the impact of CLA feeding on the immune response, even though liver fat storage cell infiltration, which plays an important role in liver regeneration, increased during CLA feeding of the piglets.

Lactic acid bacteria affect serum cholesterol levels, harmful fecal enzyme activity, and fecal water content

Do Kyung Lee — 2009-06-11T00:00:00Z

Background: Lactic acid bacteria (LAB) are beneficial probiotic organisms that contribute to improved nutrition, microbial balance, and immuno-enhancement of the intestinal tract, as well as lower cholesterol. Although present in many foods, most trials have been in spreads or dairy products. Here we tested whether Bifidobacteria isolates could lower cholesterol, inhibit harmful enzyme activities, and control fecal water content. Methods: In vitro culture experiments were performed to evaluate the ability of Bifidobacterium spp. isolated from healthy Koreans (20~30 years old) to reduce cholesterol-levels in MRS broth containing polyoxyethanylcholesterol sebacate. Animal experiments were performed to investigate the effects on lowering cholesterol, inhibiting harmful enzyme activities, and controlling fecal water content. For animal studies, 0.2 ml of the selected strain cultures (10^8~10^9 CFU/ml) were orally administered to SD rats (fed a high-cholesterol diet) every day for 2 weeks. Results: B. longum SPM1207 reduced serum total cholesterol and LDL levels significantly (p<0.05), and slightly increased serum HDL. B. longum SPM1207 also increased fecal LAB levels and fecal water content, and reduced body weight and harmful intestinal enzyme activities. Conclusions: Daily consumption of B. longum SPM1207 can help in managing mild to moderate hypercholesterolemia, with potential to improve human health by helping to prevent colon cancer and constipation.

Fatty acid patterns early after premature birth, simultaneously analysed in mothers' food, breast milk and serum phospholipids of mothers and infants.

Karl-Goran Sabel — 2009-06-10T00:00:00Z

Background: The supply of long-chain polyunsaturated fatty acids via the placenta is interrupted in premature infants, making them exclusively dependent on breast milk, which varies in fatty acid (FA) concentrations depending on the mother's diet.ObjectiveTo in a longitudinal study explore the relation between FA status in mothers and infants from an unselected cohort of prematures, not requiring intensive care.DesignBreast milk and mothers' and infants' plasma phospholipid FA concentrations from birth to 44 weeks of gestational age were analysed and compared with mothers' food intake, assessed using a 3-day diary. Fatty acids were analysed by capillary gas-liquid chromatography. Results: The energy intake was low in 75% of mothers, and 90% had low intake of essential FAs (EFAs). Dietary linoleic acid (LA, 18:2w6), but not w3 FAs, correlated to concentrations in breast milk. Infants' plasma and breast milk correlated for arachidonic (AA, 20:4w6), eicosapentaenoic (EPA, 20:5w3) and docosahexaenoic (DHA, 22:6w3) acids. A high concentration of mead acid (20:3w9) in the infants at birth correlated negatively to the concentrations of LA, AA and w3 FAs. Infants of mothers who stopped breastfeeding during the study period showed decreased DHA concentrations and increased w6/w3 ratios, with the opposite FA pattern seen in the mothers' plasma. Conclusion: Although dietary w3 FAs were insufficient in an unselected cohort of mothers of premature infants, breastfeeding resulted in increased levels of DHA in the premature infants at the expense of the mothers, suggesting a general need to increase dietary w3 FAs during pregnancy and lactation.

Lipoprotein-associated phospholipase A2 (Lp-PLA2) activity, platelet-activating factor acetylhydrolase (PAF-AH) in leukocytes and body composition in healthy adults

Paraskevi Detopoulou — 2009-06-05T00:00:00Z

Background: Lipoprotein-associated phospholipase A2 (Lp-PLA2) also known as serum platelet activating factor acetylhydrolase (PAF-AH) activity constitutes a novel risk marker for cardiovascular disease. Leukocytes constitute one main cellular source of circulating Lp-PLA2. The aim of the present study was to evaluate the association of both serum and leukocyte PAF-AH activities with fat distribution and lean tissue. One hundred healthy volunteers without cardiovascular disease history participated in this study (n = 52 men, 44 ± 13 years and n = 48 women, 43 ± 13 years). Body composition was assessed with dual-energy X-ray absorptiometry, while anthropometrical indices were also measured. The activity of Lp-PLA2 and levels of lipid and glycemic parameters were determined in fasting samples. Results: Mean Lp-PLA2 activity was 24.8 ± 4.5 and 19.6 ± 5.0 nmol/min/mL in men and women, respectively (P < 0.001). Mean activity of PAF-AH in leukocyte homogenates was 386 ± 127 pmol/min/mg and 292 ± 92 pmol/min/mg in men and women, correspondingly (P < 0.001). In multiple regression models upper and total adiposity measures were positively associated with Lp-PLA2 activity in men after adjusting for LDL-cholesterol, age, smoking, hs-CRP and physical activity, whereas no associations were found with PAF-AH leukocyte homogenates activity. Hierarchical analysis revealed that the variables with the highest explanatory ability of Lp-PLA2 activity in men, were DXA deriving L1–L4 region of interest and arms fat (increase in R2 = 0.136, P = 0.005 and increase in R2 = 0.118, P = 0.009, respectively), followed by trunk fat and total fat. In women, no association of body composition variables with Lp-PLA2 nor PAF-AH leukocyte homogenates activity was found. Conclusion: Lp-PLA2 activity is differentiated across levels of adiposity and topology of adipose tissue, whereas no association was found regarding PAF-AH leukocyte homogenates activity. Our findings suggest that Lp-PLA2 may compensate for the adiposity-associated increases in inflammatory and oxidative burden, in men.

The effect of dietary red palm oil on the functional recovery of the ischaemic/reperfused isolated rat heart: the involvement of the PI3-Kinase signaling pathway

Anna-Mart Engelbrecht — 2009-05-29T00:00:00Z

We have previously shown that dietary red palm oil (RPO) supplementation improves functional recovery in hearts subjected to ischaemia/reperfusion-induced injury. Unfortunately, the cellular and molecular mechanisms responsible for this phenomenon are still poorly understood and no knowledge exists regarding the effects of RPO supplementation on the phosphoinositide 3-kinase (PI3-K) signaling pathway and apoptosis during ischaemia/reperfusion injury. Therefore, the aims of the present study were three fold: (i) to establish the effect of RPO on the functional recovery of the heart after ischaemia/reperfuion injury; (ii) to determine the effect of the PI3-K pathway in RPO-induced protection with the aid of an inhibitor (wortmannin); and (iii) to evaluate apoptosis in our model. Wistar rats were fed a standard rat chow control diet or a control diet plus 7 g RPO/kg for six weeks. Hearts were excised and mounted on a Langendorff perfusion apparatus. Mechanical function was measured after a 25 min period of total global ischaemia followed by 30 minutes of reperfusion. Hearts subjected to the same conditions were freeze-clamped for biochemical analysis at 10 min during reperfusion to determine the involvement of the PI3-Kinase signaling pathway and apoptosis in our model. Dietary RPO supplementation significantly increased % rate pressure product recovery during reperfusion (71.0 ± 6.3% in control vs 92.36 ± 4.489% in RPO; p < 0.05). The % rate pressure product recovery was significantly reduced when wortmannin was added during perfusion (92.36 ± 4.489% in the RPO group vs 75.21 ± 5.26% in RPO + Wm). RPO + Wm also significantly attenuated PI3-K induction compared with the RPO group (59.2 ± 2.8 pixels in RPO vs 37.9 ± 3.4 pixels in RPO + Wm). We have also demonstrated that PI3-K inhibition induced PARP cleavage (marker of apoptosis) in the hearts during ischaemia/reperfusion injury and that RPO supplementation counteracted this effect.

Is adiponectin associated with acute myocardial infarction in Iranian non obese patients?

Mohammad Shojaie — 2009-05-28T00:00:00Z

BackgroundsAdiponectin is an adipose tissue-derived mediator with significant anti-atherogenic properties. A few studies were done in acute phase of myocardial infarction especially in non obese patients. We design a study to investigate the association between adiponectin concentration and acute phase of myocardial infarction in non obese patients. Methods: This case-control study was done in Paymaneah Hospital (Jahrom, Iran) from Feb 2007 to May 2008. Plasma adiponectin levels were measured in 43 patients with AMI (mean age: 62.7 ± 13.3 years, male: 67.4%) at the first 24 hours of admission and 43 normal controls (mean age: 62.1 ± 12.3 years, male: 55.8%) matched for age, sex and other CAD risk factors. Results: Adiponectin levels in patients with AMI (3.36 μg/mL) were significantly lower than that of the control group (5.03 μg/mL) (p < 0.0001). Lower adiponectin were independently associated with higher risk of AMI (odds ratio = 8.97; 95% CIs: 2.3–34.5; p = 0.001). Adiponectin levels negatively correlated with triglyceride (r = -0.46, p = 0.002) and total cholesterol (r = -0.32, p = 0.03) in the case group and with body mass index (BMI) in control subjects. Conclusion: The present study showed that adiponectin was associated with AMI in non obese patients but it is not related to sex, age and other CAD risk factors.