No abstract

High density lipoprotein (HDL) particles are believed to be protective due to their inverse correlation with the prevalence of cardiovascular diseases. However, recent studies show that in some conditions such as heart disease and diabetes, HDL particles can become dysfunctional. Great attention has been directed toward HDL particle composition because the relative abundances of HDL constituents determine HDL's functional properties. A key factor to consider when studying the structure and composition of plasma particles is the protein glycosylation. Here, we profile the O- and N-linked glycosylation of HDL associated-proteins including the truncated form of Apo CIII and their glycan heterogeneity in a site-specific manner. Apolipoprotein CIII, fetuin A, and alpha 1 antitrypsin are glycoproteins associated with lipoproteins and are implicated in many cardiovascular and other disease conditions. A targeted method (UHPLC-QQQ) was used to measure the glycoprotein concentrations and site-specific glycovariations of the proteins in human plasma and compared with HDL particles isolated from the same plasma samples. The proteins found in the plasma are differentially glycosylated compared to those isolated in HDL. The results of this study suggest that glycosylation may play a role in protein partitioning in the blood, with possible functional implications.

Since HDL glycoprofiles are associated with HDL functional capacity we set out to determine whether diet can alter the glycoprofiles of key HDL-associated proteins, including ApoE, a potent driver of chronic disease risk. Ten healthy subjects consumed a fast food (FF) and a Mediterranean (Med) diet for 4 days in randomized order, with a 4-day wash-out between treatments. A multiple reaction monitoring (MRM) method was used to characterize the site-specific glycoprofiles of HDL proteins, and HDL functional capacity was analyzed. We describe for the first time that ApoE has 7 mucin-type Oglycosylation sites, which were not affected by short-term diet. The glycoprofiles of other HDLassociated proteins were also unaffected, except a di-sialylated ApoC-III glycan was enriched after Med diet, while a non-sialylated ApoC-III glycan was enriched after FF diet. Twenty-five individual glycopeptides were significantly correlated with cholesterol efflux capacity and 21 glycopeptides were correlated with immunomodulatory capacity. Results from this study indicate that the glycoprofiles of HDL-associated proteins including ApoE are correlated with HDL functional capacity but generally unaffected by diet in the short-term, except ApoC-III sialylation. These results suggest that HDL protein glycoprofiles are affected by both acute and long-term factors, and may be useful for biomarker discovery.

Introduction: HDL is associated with increased longevity and protection from multiple chronic diseases. The major HDL protein ApoA-I has a half-life of about 4 days, however, the effects of diet on the composition of HDL particles at this time scale have not been studied. Objectives: The objective of this study is to investigate the short term dietary effect on HDL lipidomic composition. Methods: In this randomized order cross-over study, ten healthy subjects consumed a Mediterranean (Med) and a fast food (FF) diet for 4 days, with a 4-day wash-out between treatments. Lipidomic composition was analyzed in isolated HDL fractions by an untargeted LC-MS method with 15 internal standards. Results: HDL PE content was increased by FF diet, and 41 out of 170 lipid species were differentially affected by diet. Saturated fatty acids (FA) and odd chain FA were enriched after FF diet, while very-long chain FA and unsaturated FA were enriched after Med diet. The composition of PC, TG and CE were significantly altered to reflect the FA composition of the diet whereas the composition of SM and ceramides were generally unaffected. Conclusion: Results from this study indicate that the HDL lipidome is widely remodeled within 4 days of diet change and that certain lipid classes are more sensitive markers of diet whereas other lipid classes are better indicators of non-dietary factors.

CVD and associated metabolic diseases are linked to chronic inflammation, which can be modified by diet. The objective of the present study was to determine whether there is a difference in inflammatory markers, blood metabolic and lipid panels and lymphocyte gene expression in response to a high-fat dairy food challenge with or without milk fat globule membrane (MFGM). Participants consumed a dairy product-based meal containing whipping cream (WC) high in saturated fat with or without the addition of MFGM, following a 12 h fasting blood draw. Inflammatory markers including IL-6 and C-reactive protein, lipid and metabolic panels and lymphocyte gene expression fold changes were measured using multiplex assays, clinical laboratory services and TaqMan real-time RT-PCR, respectively. Fold changes in gene expression were determined using the Pfaffl method. Response variables were converted into incremental AUC, tested for differences, and corrected for multiple comparisons. The postprandial insulin response was significantly lower following the meal containing MFGM (P < 0·01). The gene encoding soluble epoxide hydrolase (EPHX2) was shown to be more up-regulated in the absence of MFGM (P = 0·009). Secondary analyses showed that participants with higher baseline cholesterol:HDL-cholesterol ratio (Chol:HDL) had a greater reduction in gene expression of cluster of differentiation 14 (CD14) and lymphotoxin β receptor (LTBR) with the WC+MFGM meal. The protein and lipid composition of MFGM is thought to be anti-inflammatory. These exploratory analyses suggest that addition of MFGM to a high-saturated fat meal modifies postprandial insulin response and offers a protective role for those individuals with higher baseline Chol:HDL.

Purpose of reviewEating behaviors and dietary patterns begin in early childhood and persist into adolescence and adulthood, affecting lifelong acute and chronic disease risk. Vegetables provide a high density of necessary vitamins, minerals, and fiber. Dietary intake data show that children of all ages consume below the recommended range for vegetables. Pediatric providers are optimally positioned to promote vegetable intake in childhood. This review seeks to summarize lessons learned from behavioral interventions useful in the pediatric primary care setting to improve vegetable intake.Recent findingsTen published studies tested behavioral interventions in primary care to increase child vegetable intake. Strategies tested include teaching healthy eating behaviors and role modeling to parents of infants, and motivational interviewing paired with frequent office visits and reminders for families of older children and adolescents. Some strategies suggested positive change, despite study quality being limited by underpowered samples, heterogeneity of outcome measures, and statistical analytic approach.SummaryIncreased vegetable intake was achieved in infants through parental role-modeling when providers emphasized healthy dietary choices in parents. Older children increased their vegetable intake with motivational interviewing and frequent reminders from providers. Despite the high prevalence of inadequate vegetable intake among children, at present, there is only a modest body of literature to help guide pediatric providers in implementing practice-based interventions to improve vegetable intake in childhood, highlighting a need for high-quality research in this area.

Although HDL cholesterol (HDL-C) levels are protective against cardiovascular disease (CVD) risk, raising HDL-C pharmaceutically has not led to improvements in cardiovascular outcomes. It is becoming clear that HDL composition and function are more important than HDL concentrations in determining risk. This study set out to determine whether glycosylation differences in HDL-associated glycoproteins affect HDL’s anti-inflammatory function. HDL were purified from healthy subjects (n=10), who consumed in randomized order a fast food (FF) diet and a Mediterranean (Med) diet for 4 days, with a 4-day washout between arms. All foods were provided in this isocaloric cross-over intervention trial, which was approved by the UC Davis IRB. Concentrations of HDL-bound serum amyloid A (SAA), apolipoprotein A-I (ApoA-I), apolipoprotein C-III (ApoC-III), α-1-antitrypsin (A1AT), and α-2-HS-glycoprotein (A2HSG); and the site-specific glycosylation of ApoC-III, A1AT, and A2HSG were measured. Secretion of TNF-α in stimulated monocytes was measured to assess HDL anti-inflammatory function. HDL glycosylation was altered by the dietary interventions and correlated with changes in the amount of TNF-α secreted by stimulated monocytes. HDL glycosylation profiles were different in response to the FF diet vs. the Med diet. HDL with a diminished capacity to suppress TNF-α secretion were enriched in ApoC-III and desialylated A2HSG, depleted in A1AT, and had lower levels of sialylation across glycoproteins. Our results demonstrate that HDL glycoprotein composition, including site-specific glycosylation, is responsive to dietary intervention and correlates with HDL’s ability to modulate TNF-α response in stimulated monocytes. These data suggest that the measurement of HDL glycosylation profiles may be useful in stratifying CVD risk and detecting individuals with impaired HDL anti-inflammatory function.

ObjectiveTo test for a difference in lymphocyte gene expression in response to a high fat dairy challenge with or without milk fat globule membrane (MFGM).MethodsData was analyzed from twenty individuals with BMI > 25.0 kg/m2. On two separate occasions, each participant consumed a dairy‐based meal high in saturated fat with or without the addition of MFGM, following a 12‐hour fasting blood draw. Inflammatory markers including interleukin‐6 (IL‐6) and C‐reactive protein (CRP), lipid and metabolic panels, and lymphocyte gene expression fold changes were measured using multi‐plex assays, clinical lab services, and TaqMan RT‐PCR, respectively. Fold changes were determined using the Pfaffl method, tested for differences through Wilcoxon Signed Rank, and corrected for multiple comparisons. Postprandial responses were quantified using incremental area under the curve (iAUC). Data was analyzed in Microsoft Excel and JMP Pro 13. Correlation analysis was used to determine associations between markers.ResultsThe median postprandial insulin response was found to be significantly lower following the meal containing MFGM (p=0.0003). Out of 56 genes analyzed, EPHX2 was shown to be more up‐regulated in the absence of MFGM (p=0.009). The median gene expression was lower and had a narrower response range when MFGM was added to the high‐fat test meal.ConclusionThe protein and lipid composition of MFGM is thought to be anti‐inflammatory. These exploratory analyses suggest that addition of MFGM to a high saturated fat meal may attenuate the upregulation of soluble epoxide hydrolase gene expression. Changes in inflammatory markers are important for determining a patient's inflammatory status, which is useful for the development of personalized nutrition and medicine, and disease prevention.This study is registered on ClinicalTrials.gov Identifier: NCT01811329Support or Funding InformationThis project was made possible by support from the National Dairy Council, Rosemont, IL. and the USDA, Agricultural Research Service, Western Human Nutrition Research CenterThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.