Publications (49) View all
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Article: Lipidomic analysis of human plasma reveals ether-linked lipids that are elevated in morbidly obese humans compared to lean.
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ABSTRACT: BACKGROUND: Lipidomic analysis was performed to explore differences in lipid profiles between plasma from lean and obese subjects, followed by in vitro methods to examine a role for the identified lipids in endothelial cell pathophysiology. METHODS: Plasma was collected from 15 morbidly obese and 13 control subjects. Lipids were extracted from plasma and analyzed using LC/MS, and MS/MS to characterize lipid profiles and identify lipids that are elevated in obese subjects compared to lean. RESULTS: Orthogonal partial least squares-discriminant analysis (OPLS-DA) modelling showed that lipid profiles were significantly different in obese subjects compared to lean. Analysis of lipids that were driving group separation in the OPLS-DA model and that were significantly elevated in the obese group led to identification of a group of ether-linked phosphatidylcholine (PC) and phosphatidylethanolamine (PE) lipids of interest. Treatment of human coronary artery endothelial cells with the ether-linked phosphatidylethanolamine induced expression of cell adhesion molecules, a hallmark of endothelial cell activation. However, oxidized phosphatidylcholine products that can induce endothelial cell activation in vitro, were not significantly different between groups in vivo. CONCLUSION: These data suggest a role for ether-linked lipids in obesity associated dyslipidemia and vascular disease.Diabetology and Metabolic Syndrome 05/2013; 5(1):24. · 1.53 Impact Factor -
Article: Cardiometabolic plasticity in response to a short-term diet and exercise intervention in young Hispanic and nonHispanic white adults.
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ABSTRACT: Young adult Mexican Americans (MA) exhibit lower insulin sensitivity (Si) than nonHispanic whites (NHW), even when controlling for fitness and adiposity. It is unclear if MA are as responsive to the same lifestyle intervention as NHW. We developed a model to examine cardiometabolic plasticity (i.e., changes in Si and plasma lipids) in MA compared to NHW adults in response to a diet-exercise intervention. Sedentary subjects (20 NHW: 11F, 9M, 23.0 y, 25.5 kg/m(2); 17 MA: 13F, 4M, 22.7 y, 25.4 kg/m(2)) consumed their habitual diets and remained sedentary for 7 days, after which fasting blood samples were obtained, and a 3-h intravenous glucose tolerance test (IVGTT) was performed with the insulin area under the curve (IAUC) used to estimate Si. Subjects then completed a 7-day diet/exercise intervention (diet: low saturated fat, low added sugar, high fiber; exercise: cycling, six total sessions lasting 40-45 min/session at 65% VO(2) max). Pre-intervention tests were repeated. Pre intervention IAUC was 28% higher (p<0.05) in MA (IAUC pre = 2298 µU*180 min/mL) than in NHW (IAUC = 1795 µU*180 min/mL). Following the intervention, there was a significant reduction in IAUC in MA (29%) and NHW (32%), however, the IAUC remained higher (p<0.05) for MA (post = 1635 µU*180 min/mL) than for NHW (post = 1211 µU*180 min/mL). Pre test plasma lipids were not different in MA compared to NHW. Plasma cholesterol and TG concentrations significantly improved in both groups, but concentrations of low density lipoprotein-cholesterol and small dense LDL particles significantly improved only in the NHW. With a short-term diet-exercise intervention, the magnitude of improvements in Si and serum cholesterol and TG in Hispanics are similar to those in NHW. However, because at the outset MA were less insulin sensitive compared to NHW, within the short timeframe studied the ethnic gap in insulin sensitivity remained.PLoS ONE 01/2011; 6(2):e16987. · 4.09 Impact Factor -
Article: Nitrogen balance in older individuals in energy balance depends on timing of protein intake.
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ABSTRACT: To explore whether nitrogen retention can differ on an isonitrogenous diet by changing when protein is consumed, we performed a short-term study in older individuals (64.5 ± 2.0 years) performing daily exercise while in energy balance. Participants consumed an isonitrogenous-isocaloric diet with the timing of a protein or carbohydrate beverage after exercise (protein after exercise [PRO], carbohydrate after exercise [CHO]) versus earlier in the day. Three-day mean energy balance (PRO: 202 ± 36 kcal and CHO: 191 ± 44 kcal; p = .68) did not differ between trials, but 3-day mean nitrogen balance was significantly more positive in the PRO (1.2 ± 0.32 g N) trial than the CHO trial (0.8 ± 0.45 g N; p < .05). Older individuals were better able to maintain nitrogen balance by simply changing when a portion of an identical amount of daily protein was consumed.The Journals of Gerontology Series A Biological Sciences and Medical Sciences 10/2010; 65(10):1068-76. · 4.60 Impact Factor -
Article: Learning from legacies: fiber types, phenotypes, and human performance.
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ABSTRACT: N/A.Journal of Applied Physiology 04/2010; 108(6):1456-7. · 3.75 Impact Factor -
Article: Omega-3 fatty acids and lipoprotein associated phospholipase A(2) in healthy older adult males and females.
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ABSTRACT: Lipoprotein associated phospholipase A(2) (Lp-PLA(2)) is a novel inflammatory factor that has been independently associated with stroke and cardiovascular disease (CVD). Omega-3 fats have been implicated in reducing inflammation associated with CVD. The aim of this study was to determine if an 8-week isocaloric diet supplemented with eicosapentaenoic acid (EPA) and docosahexaenoic (DHA) in the form of fish oil or α-linolenic acid (ALA) in the form of flaxseed oil would alter Lp-PLA(2) among healthy adults ages 50 years and older. Fifty-nine healthy adults (~75% female, average age 61 years) were randomized to one of three groups with equal amounts of total fat intake. All capsules contained ~1 g of fat. The control group (n = 19) consumed olive oil capsules (~11 g/day); the ALA group (n = 20) consumed flaxseed oil capsules (~11 g/day) and the EPA/DHA group (n = 20) consumed fish oil capsules (~2 g/day + 9 g/day of olive oil). Fasting blood samples were obtained before and after the 8-week intervention for determination of Lp-PLA(2) mass and activity as well as lipid values. We did not find any significant changes in Lp-PLA(2) mass or activity after the intervention in any of the groups; however, change in oxidized LDL was associated with change in Lp-PLA(2) mass (r = 0.37, p < 0.01). Supplementing the diet with omega-3 fatty acids for 8-weeks did not influence Lp-PLA(2) activity or mass among older adults; altering oxidized LDL may be necessary to see changes in Lp-PLA(2) levels.European Journal of Nutrition 04/2011; 50(3):185-93. · 2.75 Impact Factor
