Many
of the functional proteins and lipids in high density lipoprotein
(HDL) particles are potentially glycosylated, yet very little is known
about the glycoconjugates of HDL. In this study, HDL was isolated
from plasma by sequential micro-ultracentrifugation, followed by glycoprotein
and glycolipid analysis. N-Glycans, glycopeptides, and gangliosides
were extracted and purified followed by analysis with nano-HPLC Chip
quadrupole time of flight mass spectrometry and MS/MS. HDL particles
were found to be highly sialylated. Most of the N-glycans (∼90%)
from HDL glycoproteins were sialylated with one or two neuraminic
acids (Neu5Ac). The most abundant N-glycan was a biantennary complex
type glycan with two sialic acids (Hexose5HexNAc4Neu5Ac2) and was found in multiple glycoproteins using
site-specific glycosylation analysis. The observed O-glycans were
all sialylated, and most contained a core 1 structure with two Neu5Acs,
including those that were associated with apolipoprotein CIII (ApoC-III)
and fetuin A. GM3 (monosialoganglioside, NeuAc2–3Gal1–4Glc–Cer)
and GD3 (disialoganglioside, NeuAc2–8NeuAc2–3Gal1–4Glc–Cer)
were the major gangliosides in HDL. A 60% GM3 and 40% GD3 distribution
was observed. Both GM3 and GD3 were composed of heterogeneous ceramide
lipid tails, including d18:1/16:0 and d18:1/23:0. This report describes
for the first time a glycomic approach for analyzing HDL, highlighting
that HDL are highly sialylated particles.
Meals high in SFA, particularly palmitate, are associated with postprandial inflammation
and insulin resistance. Milk fat globule membrane (MFGM) has anti-inflammatory properties
that may attenuate the negative effects of SFA-rich meals. Our objective was to examine
the postprandial metabolic and inflammatory response to a high-fat meal composed of palm
oil (PO) compared with PO with an added dairy fraction rich in MFGM (PO+MFGM) in
overweight and obese men and women (n 36) in a randomised,
double-blinded, cross-over trial. Participants consumed two isoenergetic high-fat meals
composed of a smoothie enriched with PO with v. without a cream-derived
complex milk lipid fraction ( dairy fraction rich in MFGM) separated by a washout of 1–2
weeks. Serum cytokines, adhesion molecules, cortisol and markers of inflammation were
measured at fasting, and at 1, 3 and 6 h postprandially. Glucose, insulin and lipid
profiles were analysed in plasma. Consumption of the PO + MFGM v. PO meal
resulted in lower total cholesterol (P = 0·021), LDL-cholesterol
(P = 0·046), soluble intracellular adhesion molecule
(P = 0·005) and insulin (P = 0·005) incremental AUC, and
increased IL-10 (P = 0·013). Individuals with high baseline C-reactive
protein (CRP) concentrations (≥3 mg/l, n 17) had higher
(P = 0·030) insulin at 1 h after the PO meal than individuals with CRP
concentrations <3 mg/l (n 19). The addition of MFGM attenuated
this difference between CRP groups. The addition of a dairy fraction rich in MFGM
attenuated the negative effects of a high-SFA meal by reducing postprandial cholesterol,
inflammatory markers and insulin response in overweight and obese individuals,
particularly in those with elevated CRP.
Dietary recommendations suggest decreased consumption of SFA to minimise CVD risk;
however, not all foods rich in SFA are equivalent. To evaluate the effects of SFA in a
dairy food matrix, as Cheddar cheese, v. SFA from a vegan-alternative
test meal on postprandial inflammatory markers, a randomised controlled cross-over trial
was conducted in twenty overweight or obese adults with metabolic abnormalities.
Individuals consumed two isoenergetic high-fat mixed meals separated by a 1- to 2-week
washout period. Serum was collected at baseline, and at 1, 3 and 6 h postprandially and
analysed for inflammatory markers (IL-6, IL-8, IL-10, IL-17, IL-18, TNFα, monocyte
chemotactic protein-1 (MCP-1)), acute-phase proteins C-reactive protein (CRP) and serum
amyloid-A (SAA), cellular adhesion molecules and blood lipids, glucose and insulin.
Following both high-fat test meals, postprandial TAG concentrations rose steadily
(P < 0·05) without a decrease by 6 h. The incremental AUC (iAUC)
for CRP was significantly lower (P < 0·05) in response to the
cheese compared with the vegan-alternative test meal. A treatment effect was not observed
for any other inflammatory markers; however, for both test meals, multiple markers
significantly changed from baseline over the 6 h postprandial period (IL-6, IL-8, IL-18,
TNFα, MCP-1, SAA). Saturated fat in the form of a cheese matrix reduced the iAUC for CRP
compared with a vegan-alternative test meal during the postprandial 6 h period. The study
is registered at clinicaltrials.gov under NCT01803633.
The morphology of retinal ganglion cells projecting to the superior colliculus (SC) of the thirteen-lined ground squirrel (Spermophilus tridecemlineatus) was studied after retrogradely labeling the cells with cholera toxin subunit B. On the basis of previous reports, labeled cells were classified as small (6-10 microm in soma diameter), medium (11-14 microm), or large (>14 microm). A total of 3,427 cells were studied. Small cells constituted 78% of the population, 21% were medium cells, and only 1% were classified as large. The morphology of medium-sized cells was studied in more detail because large cells were few in number and the staining of the dendritic tree of small cells was not optimal. The best labeled medium-sized cells were classified on the basis of the shape and size of their dendritic tree and the pattern of dendritic ramification. Four types were identified among the medium-sized ganglion cells. Two types were classified as symmetric delta-like and asymmetric delta-like cells considering the relative symmetric or asymmetric distribution of their dendritic branches and their similarities with the delta type of the cat. Approximately 52% of all the medium-sized cells studied were symmetrical delta-like, and 19% were classified as asymmetrical delta-like. These cells were also very similar to the symmetrical and asymmetrical directionally selective ganglion cells described in rabbit retina. Other cells were termed beta-like. They had the smallest dendritic tree diameter, and their tree size seemed to be related to retinal eccentricity. Medium beta-like cells comprised approximately 21% of all cells projecting to the SC. The fourth type was termed "acute angle" because most of their dendritic branches were relatively straight and formed acute angles (10-45 degrees) at their branching points. These cells were few in number (approximately 8% of all medium-sized cells studied) and did not resemble any reported previously in cats. Thus, a variety of morphological types of retinal ganglion cells projected to the SC. Of these, the symmetrical and asymmetrical delta-like cells appeared to correspond to the directionally selective type described in the ground squirrel (Michael, C.R. [1968] J. Neurophysiol. 31:257-267) and reported in the rabbit retina.
BackgroundInflammation is associated with increased bone resorption; the role of inflammation in postprandial bone turnover has not been explored. Consumption of milk fat globule membrane (MFGM) reduces inflammation in animal models. This study aimed to measure postprandial changes in bone turnover after intake of high saturated fat test meals, with- and without the anti-inflammatory ingredient MFGM.MethodsSubjects (n = 36 adults) were obese (BMI 30–39.9 kg/m2) or overweight (BMI 25–29.9 kg/m2) with two traits of Metabolic Syndrome. Subjects consumed a different test meal on four occasions at random; blood draws were taken at baseline and 1, 3, and 6 h postprandial. Test meals included whipping cream (WC), WC + MFGM, palm oil (PO) and PO + MFGM. Biomarkers of bone turnover and inflammation were analyzed from all four time points.ResultsTest meal (treatment) by time interactions were significant for bone resorption marker C-telopeptide of type 1 collagen (CTX) (p < 0.0001) and inflammatory marker interleukin 10 (IL-10) (p = 0.012). Significant differences in overall postprandial response among test meals were found for CTX and soluble intercellular adhesion molecule (sICAM), with the greatest overall postprandial suppression of CTX occurring in meals containing MFGM. However, test meal by MFGM interactions were non- significant for bone and inflammatory markers. Correlations between CTX and inflammatory markers were non-significant.ConclusionThis exploratory analysis advances the study of postprandial suppression of bone turnover by demonstrating differing effects of high SFA meals that contained MFGM; however MFGM alone did not directly moderate the difference in postprandial CTX response among test meals in this analysis. These observations may be useful for identifying foods and ingredients which maximize the suppression of bone resorption, and for generating hypotheses to test in future studies examining the role of inflammation in postprandial bone turnover.Trial registrationClinicaltrials.gov NCT01811329. Registered 11 March 2013.Electronic supplementary materialThe online version of this article (doi:10.1186/s12986-017-0189-z) contains supplementary material, which is available to authorized users.
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