Postprandial Phase Research Articles

Hemodynamics assessed via approximate entropy analysis of impedance cardiography time series: effect of metabolic syndrome

The metabolic syndrome (MS), a predisposing condition for cardiovascular disease, presents disturbances in hemodynamics; impedance cardiography (ICG) can assess these alterations. In subjects with MS, the morphology of the pulses present in the ICG time series is more irregular/complex than in normal subjects. Therefore, the aim of the present study was to quantitatively assess the complexity of ICG times series in 53 patients, with or without MS, through a nonlinear analysis algorithm, the approximate entropy, a method employed in recent years for the study of several biological signals, which provides a scalar index, ApEn. We correlated ApEn computed from ICG times series data during fasting and postprandial phase with the presence of alterations in the parameters defining MS [Adult Treatment Panel (ATP) III (Grundy SM, Brewer HB Jr, Cleeman JI, Smith SC Jr, Lenfant C; National Heart, Lung, and Blood Institute; American Heart Association. Circulation 109: 433-438, 2004) and the International Diabetes Federation (IDF) definition]. Results show that ApEn was significantly higher in subjects with MS compared with those without (1.81 ± 0.09 vs. 1.65 ± 0.13; means ± SD; P = 0.0013, with ATP III definition; 1.82 ± 0.09 vs. 1.67 ± 0.12; P = 0.00006, with the IDF definition). We also demonstrated that ApEn increase parallels the number of components of MS. ApEn was then correlated to each MS component: mean ApEn values of subjects belonging to the first and fourth quartiles of the distribution of MS parameters were statistically different for all parameters but HDL cholesterol. No difference was observed between ApEn values evaluated in fasting and postprandial states. In conclusion, we identified that MS is characterized by an increased complexity of ICG signals: this may have a prognostic relevance in subjects with this condition.

A high-fat meal promotes lipid-load and apolipoprotein B-48 receptor transcriptional activity in circulating monocytes

The postprandial metabolism of dietary fats results in the production of apolipoprotein B-48 (apoB48)-containing triglyceride-rich lipoproteins (TRLs), which cause rapid receptor-mediated macrophage lipid engorgement via the apoB48 cell surface receptor (apoB48R). Monocytes circulate together with apoB48-containing TRLs in the postprandial bloodstream and may start accumulating lipids even before their migration to tissues and differentiation to macrophages. We sought to determine whether circulating monocytes are equipped with apoB48R and whether, in the postprandial state, circulating monocytes accumulate lipids and modulate apoB48R transcriptional activity after intake of a high-fat meal. In a crossover design, we studied the effect of a high-fat meal on fasting and postprandial concentrations of triglycerides, free fatty acids, cholesterol, and insulin in 12 healthy men. TRLs and monocytes were freshly isolated at fasting, hourly until the postprandial peak, and at the late postprandial phase. TRLs were subjected to triglycerides, apoB48, and apolipoprotein B-100 analyses; and lipid accumulation and apoB48R mRNA expression levels were measured in monocytes. Monocytes showed a time-dependent lipid accumulation in response to the high-fat meal, which was paralleled by an increase in apoB48R mRNA expression levels. These effects were coincident only with an increase in apoB48-containing TRLs in the postprandial phase and were also observed ex vivo in freshly isolated monocytes incubated with apoB48-containing TRLs. In a setting of abundant plasma apoB48-containing TRLs, these findings highlight the role of dietary fat in inducing lipid accumulation and apoB48R gene transcription in circulating monocytes.

POSTPRANDIAL EFFECTS OF THE MEDITERRANEAN DIET ON OXIDANT AND ANTIOXIDANT STATUS IN ELDERLY MEN AND WOMEN

POSTPRANDIAL EFFECTS OF THE MEDITERRANEAN DIET ON OXIDANT AND ANTIOXIDANT STATUS IN ELDERLY MEN AND WOMEN

Impaired hemodynamic response to meal intake in insulin-resistant subjects: an impedance cardiography approach

In the postprandial state, insulin regulates metabolic and cardiovascular responses. In insulin resistance, the insulin action is impaired at both levels. However, postprandial hemodynamic responses are poorly characterized in this setting. We investigated fasting and postprandial cardiac and vascular hemodynamic responses in subjects with and without insulin resistance. Sixty-six atherosclerosis-free, healthy volunteers were studied in a fasted state and ≤180 min after ingestion of a mixed meal. The insulin sensitivity index was determined by using a minimal model analysis; hemodynamic response was monitored by using continuous impedance cardiography that allowed a reliable beat-to-beat noninvasive evaluation of stroke volume, cardiac contractility, and several derived variables. Subjects were divided into insulin-resistant (IR; n = 33) and insulin-sensitive (IS; n = 33) groups. After fasting, IR subjects had significantly higher values of systolic and diastolic blood pressures and the systemic vascular resistance index (SVRI) than did IS subjects. In the postprandial state, acute vasodilatation was comparable and synchronous (at 30 min) in IR and IS subjects (P = 0.209), but subsequent vascular tone recovery (30-180 min) was significantly impaired in IR subjects (P = 0.018), even after adjustment for age and sex (P = 0.031). Hemodynamic dysregulation was directly correlated with metabolic disturbances in the postprandial state. In basal and postprandial states, hemodynamic variables related to cardiac function were not significantly different in IR and IS subjects. IR subjects had a worse fasting vascular performance than did IS subjects. In the postprandial phase, insulin resistance was associated with a shorter duration of vasodilatation in the absence of an altered cardiac performance. Peripheral hemodynamic alterations in fasting and postprandial states may have a negative effect on cardiovascular performance in IR patients.

Exchanging Saturated Fatty Acids for (n-6) Polyunsaturated Fatty Acids in a Mixed Meal May Decrease Postprandial Lipemia and Markers of Inflammation and Endothelial Activity in Overweight Men1–3

Postprandial lipemia, low-grade systemic inflammation, and endothelial activity are related to metabolic disorders. It is well known that dietary fatty acid composition modulates postprandial lipemia, but information on the other metabolic risk markers is limited. We therefore studied the acute effects of a meal rich in SFA compared with those of a meal rich in (n-6) PUFA on postprandial responses in overweight men who are at an increased risk to develop the metabolic syndrome and its comorbidities. In a crossover design, the effects of 50 g butter (rich in SFA) on lipemia and markers for inflammation and endothelial activity were compared with those of 50 g sunflower oil [rich in (n-6) PUFA] during an 8-h postprandial mixed meal tolerance test in 13 overweight men. Postprandial changes in serum TG were comparable between the meals (P= 0.38), except for a reduction in the incremental area under the curve (P= 0.046) in the late postprandial phase after (n-6) PUFA (125 ± 96 mmol·min·L-1) compared with SFA (148 ± 98 mmol·min·L-1). Compared with the SFA meal, the (n-6) PUFA meal decreased plasma IL-6 (P= 0.003), TNFa (P= 0.005), soluble TNF receptors I and II (sTNFr;P= 0.024 andP< 0.001, respectively), and soluble vascular cell adhesion molecule-1 (sVCAM-1;P= 0.030) concentrations. These results indicate that exchanging SFA from butterfat for (n-6) PUFA in a mixed meal may decrease postprandial lipemia and concentrations of IL-6, TNFa, sTNFr-I and -II, and sVCAM-1 in overweight men.

Proton-pump inhibitors for the treatment of functional dyspepsia

In the Rome III classification, functional dyspepsia (FD) has been further subcategorized into two different syndromes, namely, epigastric pain syndrome (EPS) and postprandial distress syndrome (PDS). Acid-related pathophysiology seems to be mainly responsible for EPS, and antisecretory agents such as proton-pump inhibitors (PPIs) seem to be effective mainly against EPS. However, recent information as to the relationship between initial duodenal acid sensitization in the early postprandial phase and delayed gastric emptying in the later postprandial phase would suggest the amelioration of PDS by antisecretory agents. In the present review, we summarized the recent literature on the direct and indirect effect of PPIs in FD (including not only Rome III, but also Rome II criteria). The effects of PPIs against FD are heterogeneous, depending on the protocol of the clinical studies, and the inclusion criteria of each randomized controlled trial (primary care or tertiary care population). As the placebo effects cannot be ignored in this disease, a placebo-controlled study would be necessary, at least for the evaluation of the effect of each agent on symptom relief in patients with FD. Further studies directly comparing PPIs with suitable placebos in terms of their effects in reducing the symptoms of endoscopically confirmed, Rome III-based FD are awaited.

Derivation of physiological inhalation rates in children, adults, and elderly based on nighttime and daytime respiratory parameters

The methodology developed in our previous studies () for the determination of physiological daily inhalation rates was improved by integrating into the calculation process, both nighttime and daytime respiratory parameters, namely oxygen uptake factors (H) and ventilatory equivalents (VQ). H values during fasting (0.2057 ± 0.0018 L of O2/kcal; mean ± SD) and postprandial phases (0.2059 ± 0.0019 L of O2/kcal) as well as VQ values for subjects at rest (27.4 ± 4.8 to 32.2 ± 3.1, unitless) and during the aggregate daytime activities (29.9 ± 4.2 to 33.7 ± 7.2) were determined and combined with published doubly labeled water measurements for the calculation of daily inhalation rates in normal-weight males and females aged 0.22–96 years (n = 1235). Depending upon the unit value chosen, the highest 99th percentiles for inhalation data were found in males aged 35 to <45 years (35.40 m3/day), 2.6 to <6 months (1.138 m3/kg-day), and 10 to <16.5 years (22.29 m3/m2-day). Means and percentiles expressed in m3/kg-day as well as in m3/m2-day suggest generally higher intakes of air pollutants in children than in adults and in males than in females (in µg/kg-day or µg/m2-day) for identical exposure concentrations and conditions. For instance, means in boys aged 2.6 to <6 months of 10.99 ± 3.50 m3/m2-day and 0.572 ± 0.191 m3/kg-day are 1.3- and 2.5-folds higher, respectively, than those in adult males 65–96 years old (8.42 ± 2.13 m3/m2-day, 0.225 ± 0.059 m3/kg-day).

Impact of a Resistant Dextrin with a Prolonged Oxidation Pattern on Day-Long Ghrelin Profile

Objectives: The effects of a new resistant dextrin ingested at breakfast on day-long metabolic parameters and ghrelin profile at subsequent lunch were investigated.Methods: In this randomized, single-blinded, crossover study, 12 healthy men ingested a standardized breakfast with 50 g of NUTRIOSE 10, a resistant dextrin (RD), or of maltodextrin (Malto) and a standardized lunch 5 hours later. Both products (RD and Malto) were derived from corn naturally rich in 13C to follow their metabolic fate (by using stable isotope analysis). Oxidation and fermentation patterns were assessed by simultaneous 13CO2/H2 breath testing. The appearance of exogenous 13C-glucose in plasma, glycemia, insulinemia, nonesterified fatty acids (NEFAs), and ghrelin concentrations were measured for 10 hours following breakfast ingestion.Results: With RD, H2 excretion (fermentation) was significantly enhanced compared with Malto, whereas the appearance of 13CO2 (oxidation) was significantly prolonged (p < 0.0001). Following breakfast, ghrelin secretion was significantly less inhibited and NEFA concentration was higher with RD (p < 0.05), but unexpectedly, both remained lower after lunch and up to T600 minutes. According to the reduced bioavailability of RD compared with Malto, the appearance of 13C-glucose in plasma (p < 0.0001) and glycemic and insulinemic responses to breakfast (p < 0.05) were significantly reduced.Conclusions: Ingestion of this new resistant dextrin at breakfast decreased ghrelin concentrations in response to the subsequent lunch, even if the caloric load ingested at breakfast was lower. This effect may be linked to the prolonged fermentation/oxidation pattern seen in the late postprandial phase (up to 10 hours after ingestion at breakfast), and thus prolonged energy release with the resistant dextrin.

Acute and second-meal effects of almond form in impaired glucose tolerant adults: a randomized crossover trial

BackgroundNut consumption may reduce the risk of developing type 2 diabetes. The aim of the current study was to measure the acute and second-meal effects of morning almond consumption and determine the contribution of different nut fractions.MethodsFourteen impaired glucose tolerant (IGT) adults participated in a randomized, 5-arm, crossover design study where whole almonds (WA), almond butter (AB), defatted almond flour (AF), almond oil (AO) or no almonds (vehicle - V) were incorporated into a 75 g available carbohydrate-matched breakfast meal. Postprandial concentrations of blood glucose, insulin, non-esterified free fatty acids (NEFA), glucagon-like peptide-1 (GLP-1) and appetitive sensations were assessed after treatment breakfasts and a standard lunch.ResultsWA significantly attenuated second-meal and daylong blood glucose incremental area under the curve (AUCI) and provided the greatest daylong feeling of fullness. AB and AO decreased blood glucose AUCI in the morning period and daylong blood glucose AUCI was attenuated with AO. WA and AO elicited a greater second-meal insulin response, particularly in the early postprandial phase, and concurrently suppressed the second-meal NEFA response. GLP-1 concentrations did not vary significantly between treatments.ConclusionsInclusion of almonds in the breakfast meal decreased blood glucose concentrations and increased satiety both acutely and after a second-meal in adults with IGT. The lipid component of almonds is likely responsible for the immediate post-ingestive response, although it cannot explain the differential second-meal response to AB versus WA and AO.

Effects of cereal breakfasts on postprandial glucose, appetite regulation and voluntary energy intake at a subsequent standardized lunch; focusing on rye products.

BackgroundRye products have been demonstrated to lower the acute insulin demand, induce a low and prolonged blood glucose response (high Glycemic Profile, GP) and reduce subclinical inflammation. These products may therefore contribute to a lowered risk of obesity, type 2 diabetes and cardio vascular disease. The objective of the present paper was to evaluate the mechanism for a reduced postprandial insulin demand with rye products, and to explore possible appetite regulating properties.Methods10 healthy subjects were served breakfast meals (50 g of available starch) with endosperm- or whole grain rye breads, with and without lactic acid, boiled whole grain rye- (RK) or wheat (WK) kernels, or white wheat bread reference (WWB) in random order in a cross-over design. Plasma concentrations of glucose, ghrelin, serum insulin, free fatty acids, adiponectin, breath hydrogen excretion (H2), and subjective satiety was evaluated during the postprandial phase. 270 min after the breakfast, an ad lib lunch buffet was served and the voluntary energy intake (EI) was registered.ResultsAll rye products and WK induced lower insulinemic indices (II) than WWB. A lower incremental insulin peak following breakfast correlated with a lower EI at lunch (r = 0.38). A low II was related to improved satiety in the early postprandial phase (fullness AUC 0-60 min, r = -0.36). RK induced a higher GP compared to WWB and WK. A higher GP was related to a lowered desire to eat before lunch (AUC 210-270) and to a lower concentration of ghrelin in the late postprandial phase after breakfast (270 min), r = -0.29 and -0.29), which in turn was related to a lower voluntary EI (r = 0.43 and 0.33). The RK breakfast improved satiety in the early postprandial phase (0-60 min) compared to WWB, and induced a lower EI at lunch (-16%). A high content of indigestible carbohydrates in the breakfast products was related to improved satiety (0-60 min, r = 0.68 for fullness), and a higher breath H2 in the late postprandial phase (120-270 and 270-390 min, r = 0.46 and 0.70). High H2 (AUC 120-270 min) also correlated with lower EI (r = -0.34).ConclusionsRye products, rich in indigestible carbohydrates, induce colonic fermentation already post the breakfast meal, and lowers acute insulin responses. A high excretion of breath H2 also correlated with a higher GP. Especially, rye kernels induced a high GP which was associated with a 16% lowering of energy intake at a subsequent lunch meal. The bulking effect of rye fiber, colonically derived fermentation metabolites, a high GP and a low insulin response possibly all contributes to the benefits on glucose- and appetite regulation seen in an acute and semi-acute perspective.

Postprandial ghrelin response is reduced in patients with Parkinson’s disease and idiopathic REM sleep behaviour disorder: a peripheral biomarker for early Parkinson’s disease?

Ghrelin, an orexigenic peptide, has multiple functions, which include promoting gastrointestinal motility and influencing higher brain functions. Experimental data suggest that ghrelin has neuroprotective potential in the MPTP mouse model of Parkinson's disease (PD). PD patients show delayed gastric emptying and other symptoms that may relate to disturbed excretion of ghrelin. No data are available on postprandial ghrelin response in patients with PD and idiopathic REM sleep behaviour disorder (iRBD)--a condition considered a putative preclinical stage of PD. We measured fasting and postprandial ghrelin serum concentrations in 20 healthy controls, 39 (including 19 drug-naïve) PD patients and 11 iRBD patients using a commercial radioimmunoassay for total ghrelin. For statistical analysis we employed ANCOVA and post-hoc testing with Bonferroni's method. Controls showed a decrease of mean fasting ghrelin serum concentrations in the early postprandial phase, followed by a recuperation starting 60 min after the test meal and reaching a maximum at 300 min. This recuperation was less pronounced in PD and iRBD; the slope of relative postprandial ghrelin recovery was different between the investigated groups (p = 0.007). Post-hoc testing showed a difference between controls and PD patients (p = 0.002) and between controls and iRBD patients (p = 0.037). The dynamic regulation of ghrelin in response to food intake is partially impaired in subjects at putative preclinical (iRBD) and clinical stages of PD. Reduced ghrelin excretion might increase the vulnerability of nigrostriatal dopaminergic neurons as suggested by animal studies. The impaired ghrelin excretion might qualify as a peripheral biomarker and be of diagnostic or therapeutic value.

Postprandial lipemia enhances the capacity of large HDL2 particles to mediate free cholesterol efflux via SR-BI and ABCG1 pathways in type IIB hyperlipidemia

Lipid and cholesterol metabolism in the postprandial phase is associated with both quantitative and qualitative remodeling of HDL particle subspecies that may influence their anti-atherogenic functions in the reverse cholesterol transport pathway. We evaluated the capacity of whole plasma or isolated HDL particles to mediate cellular free cholesterol (FC) efflux, cholesteryl ester transfer protein (CETP)-mediated cholesteryl ester (CE) transfer, and selective hepatic CE uptake during the postprandial phase in subjects displaying type IIB hyperlipidemia (n = 16). Postprandial, large HDL2 displayed an enhanced capacity to mediate FC efflux via both scavenger receptor class B type I (SR-BI)-dependent (+12%; P < 0.02) and ATP binding cassette transporter G1 (ABCG1)-dependent (+31%; P < 0.008) pathways in in vitro cell systems. In addition, the capacity of whole postprandial plasma (4 h and 8 h postprandially) to mediate cellular FC efflux via the ABCA1-dependent pathway was significantly increased (+19%; P < 0.0003). Concomitantly, postprandial lipemia was associated with elevated endogenous CE transfer rates from HDL2 to apoB lipoproteins and with attenuated capacity (-17%; P < 0.02) of total HDL to deliver CE to hepatic cells. Postprandial lipemia enhanced SR-BI and ABCG1-dependent efflux to large HDL2 particles. However, postprandial lipemia is equally associated with deleterious features by enhancing formation of CE-enriched, triglyceride-rich lipoprotein particles through the action of CETP and by reducing the direct return of HDL-CE to the liver.

Monosodium glutamate raises antral distension and plasma amino acid after a standard meal in humans

The consumption of monosodium glutamate (MSG) is advocated to elicit physiological and metabolic effects, yet these effects have been poorly investigated directly in humans and in particular in the postprandial phase. Thirteen healthy adults were supplemented for 6 days with a nutritional dose of MSG (2 g) or sodium chloride (NaCl) as control, following a crossover design. On the 7th day, they underwent a complete postprandial examination for the 6 h following the ingestion of the same liquid standard meal (700 kcal, 20% of energy as [(15)N]protein, 50% as carbohydrate, and 30% as fat) supplemented with MSG or NaCl. Real-ultrasound measures of antral area indicated a significant increased distension for the 2 h following the meal supplemented with MSG vs. NaCl. This early postprandial phase was also associated with significantly increased levels of circulating leucine, isoleucine, valine, lysine, cysteine, alanine, tyrosine, and tryptophan after MSG compared with NaCl. No changes to the postprandial glucose, insulin, glucagon-like peptide (GLP)-1, and ghrelin were noted between MSG- and NaCl-supplemented meals. Subjective assessments of hunger and fullness were neither affected by MSG supplementation. Finally, the postprandial fate of dietary N was identical between dietary conditions. Our findings indicate that nutritional dose of MSG promoted greater postprandial elevations of several indispensable amino acids in plasma and induced gastric distension. Further work to elucidate the possible sparing effect of MSG on indispensable amino acid first-pass uptake in humans is warranted. This trial was registered at clinicaltrials.gov as NCT00862017.

ORIGINAL ARTICLE: Effect of pioglitazone and acarbose on endothelial inflammation biomarkers during oral glucose tolerance test in diabetic patients treated with sulphonylureas and metformin

The increased risk of cardiovascular events in diabetic patients has been related to numerous metabolic and haemoreological factors. Some of these factors appear to be particularly evident during the post-prandial phases and to be related to peak plasma glucose level. To compare the effect of addition of pioglitazone and acarbose to sulphonylureas and metformin therapy on metabolic parameters and on markers of endothelial dysfunction and vascular inflammation in type 2 diabetic patients. We enrolled 473 caucasian type 2 diabetic patients. All patients underwent measurements of height and body weight, body mass index (BMI), glycated haemoglobin (HbA1c) , fasting plasma glucose (FPG), post-prandial plasma glucose (PPG), fasting plasma insulin (FPI), post-prandial plasma insulin (PPI), homeostasis model assessment (HOMA index), systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C), triglycerides (Tg), sICAM-1, IL-6, high-sensitivity C reactive protein (hsCRP), sVCAM-1, sE-selectin and tumour necrosis factor (TNF-α). Assessments were made at start of titration, after 3 months [before a first oral glucose tolerance test (OGTT)], after 6 months and at the study end (before a second OGTT). Two-hundred and seventy four patients completed the study: 138 were randomized to double-blind treatment with pioglitazone and 136 with acarbose. Significant BMI and weight increase were observed after full treatment in the pioglitazone group relative to the acarbose group. A decrease in glycated haemoglobin was observed after the titration period in the pioglitazone group compared to both baseline value and the acarbose group. A decrease in glycated haemoglobin was also obtained after full treatment in the pioglitazone group when compared to the end of titration period and to the acarbose group. Significant decrease in FPG was obtained in the pioglitazone group after full treatment compared to the end of titration period. Post-prandial plasma glucose decrease was observed in acarbose group compared to the baseline value and to the end of titration period. Fasting plasma insulin decreased in the pioglitazone group after both the titration period and the full treatment period compared to both the baseline value and the acarbose group. The HOMA index decreased significantly after the full treatment in pioglitazone group compared to the end of titration period and to the acarbose group. Interleukin-6 and tumour necrosis factor-α decreased after full treatment in the pioglitazone group relative to the end of titration period. Significant hsCRP decrease was obtained after the titration period when compared to the baseline value in the pioglitazone group. High-sensitivity C reactive protein decreased in the pioglitazone group after full treatment compared to the end of titration period and to the acarbose group. Pioglitazone reduces the inflammatory response to a glucose challenge more than acarbose in type 2 diabetic patients, already treated with maximal doses of sulphonylureas and metformin.

Up‐regulation of hepatic lipolysis stimulated lipoprotein receptor by leptin: a potential lever for controlling lipid clearance during the postprandial phase

As a hepatic receptor for triglyceride-rich lipoproteins, the lipolysis-stimulated lipoprotein receptor (LSR) may be involved in the dynamics of lipid distribution between the liver and peripheral tissues. Here, we explore the potential role of leptin in regulating LSR. At physiological concentrations (1-10 ng/ml), leptin increased LSR protein and mRNA levels in Hepa1-6 cells through an ERK1/2-dependent and α-amanitin-sensitive pathway. In vivo, leptin treatment of C57BL6/Rj mice (1 μg 2×/d, 8 d) led to a significant increase in hepatic LSR mRNA and protein, decreased liver triglycerides and increased VLDL secretion as compared to controls. LSR(+/-) mice with elevated postprandial lipemia placed on a high-fat (60% kcal) diet exhibited accelerated weight gain and increased fat mass as compared to controls. While plasma leptin levels were increased 3-fold, hepatic leptin receptor protein levels and phosphorylation of ERK1/2 were significantly reduced. Therefore, leptin is an important regulator of LSR protein levels providing the means for the control of hepatic uptake of lipids during the postprandial phase. However, this may no longer be functional in LSR(+/-) mice placed under a chronic dietary fat load, suggesting that this animal model could be useful for the study of molecular mechanisms involved in peripheral leptin resistance.

Hypertriglyceridemia in obese subjects: Caused by reduced apolipoprotein A5 plasma levels?

Recent evidence from a collaborative analysis demonstrates gain, that genetic variations in the A1-C3-A4-A5-Locus resultng in increased circulating triglyceride (TG) levels are associated ith coronary heart disease [1]. Therefore, it is of great interest o unravel the underlying pathophysiological mechanisms leading o elevated TG concentrations. Intestinal chylomicrons and livererived VLDL represent the two classes of lipoproteins that are esponsible for the transport of triglycerides to various body cells. n the bloodstream these triglyceride-rich lipoproteins (TRL) are ydrolysed by the action of lipoprotein lipase (LPL) and the fatty cids released are taken up by peripheral organs such as adipose issue and muscle for storage or energy production, respectively. PL mediated hydrolysis is crucially dependent on the essential ofactor apolipoprotein C2 (apoC2). The lipolytic process is augented by the presence of another apolipoprotein, apoA5 [2,3] and nhibited by apoC3 [4]. Under normal conditions, the remaining holesterol-rich remnant particles are then rapidly cleared by the iver via lipoprotein receptor-mediated endocytosis [5]. Both dysunctional vascular TRL processing and impaired hepatic remnant ptake can lead to hypertriglyceridemia. Hypertriglyceridemia is a characteristic of obesity associated etabolic abnormalities evolving from insulin resistance. Several f the molecular mechanisms leading to impaired TG clearance n insulin resistant patients can be explained by reduced insulin ensitivity in different organs as liver and adipose tissue. The roduction of large triglyceride-rich VLDL-1 particles in insulin esistant patients contributes to elevated triglyceride levels in he postprandial phase, since these VLDL are less hydrolysable nd may compete with chylomicrons [6]. Hepatic LDL receptor

A Netnographic Exploration

Levodopa (L-DOPA) is the naturally occurring precursor amino acid for dopamine and the main therapeutic agent for neurologic disorders due to dopamine depletion, such as Parkinson’s disease. l-DOPA absorption in small intestine has been suggested to be mediated by the large neutral amino acids transport machinery, but the identity of the involved transporters is unknown. Clinically, coadministration of l-DOPA and dietary amino acids is avoided to decrease competition for transport in intestine and at the blood-brain barrier. l-DOPA is routinely coadministered with levodopa metabolism inhibitors (dopa-decarboxylase and cathechol-<i>O</i>-methyl transferase inhibitors) that share structural similarity with levodopa. In this systematic study involving <i>Xenopus laevis</i> oocytes and Madin-Darby canine kidney epithelia expression systems and ex vivo preparations from wild-type and knockout mice, we identified the neutral and dibasic amino acids exchanger (antiporter) b^0,+AT-rBAT (SLC7A9-SLC3A1) as the luminal intestinal l-DOPA transporter. The major luminal cotransporter (symporter) B⁰AT1 (SLC6A19) was not involved in levodopa transport. L-Leucine and L-arginine competed with levodopa across the luminal enterocyte membrane as expected for b^0,+AT-rBAT substrates, whereas dopa-decarboxylase and cathechol-<i>O</i>-methyl transferase inhibitors had no effect. The presence of amino acids in the basolateral compartment mimicking the postprandial phase increased transepithelial levodopa transport by stimulating basolateral efflux via the antiporter LAT2-4F2 (SLC7A8-SLC3A2). Additionally, the aromatic amino acid uniporter TAT1 (SLC16A10) was shown to play a major role in l-DOPA efflux from intestinal enterocytes. These results identify the molecular mechanisms mediating small intestinal levodopa absorption and suggest strategies for optimization of delivery and absorption of this important prodrug.

Endothelial cells as targets for chylomicron remnants

Endothelial dysfunction is characterised by pro-inflammatory/pro-coagulant changes in the endothelium and supports leukocyte adhesion and transmigration, key steps in early atherogenesis. There is emerging evidence that triacylglycerol-rich lipoproteins (TGRLs) present in the circulation during the postprandial phase influence vascular inflammation but the specific contribution of the remnant lipoprotein component of TGRLs is largely unexplored and the mechanistic basis of their actions poorly defined. This article provides a brief overview of the evidence supporting direct actions of these particles on endothelial cells and highlights the importance of their fatty acid composition and oxidative state as determinants of their cellular actions.

Postprandial bone turnover is independent of calories above 250 kcal

The mechanisms causing bone turnover after food intake have not yet been elucidated. Several gut hormones are secreted in the postprandial phase, proportional to meal calorie content, and possibly one or more of these could influence bone turnover. The aim of this study was to investigate bone turnover in proportion to graded-calorie and fixed calcium containing meals. A group of healthy volunteers were given six meals with calories varying from 250 to 3000 kcal on different occasions. All the meals contained 500 mg of calcium. C-telopeptide type I collagen (CTX) was measured before and 180 min after each meal. All meals significantly reduced CTX between 35.8 +/- 5.6% and 44.8 +/- 3.8%. No significant difference in CTX was however apparent for the different calorie containing meals. Observed differences suggest a trend to greater CTX suppression with lower protein and higher fat content of meals. Changes in CTX are not proportional to calorie contents when the meals contain 500 mg of calcium. Further studies should now determine whether patients with increased bone resorption would benefit from multiple small meals to slow down the rate of bone loss.

Insulin resistance and acute coronary syndrome

Background Insulin resistance (IR), which can be quantified by HOMA index (fasting glucose X fasting insulin/22.5), is considered the “primum movens” for the development of Metabolic Syndrome. Many authors have suggested that insulin resistance could raise both incidence and mortality of coronary heart disease (CHD). IR is also associated with important predictors of cardiovascular disease, as increased concentration of LDL or triglyceride, decreased concentration of HDL, high systolic blood pressure, visceral obesity. There is accumulating evidence that chronic sub-clinical inflammation, as measured by inflammatory markers as C-reactive protein (CRP) and fibrinogen, is related with insulin resistance. Aim of the study To clarify if insulin resistance would predict cardiovascular disease independently of the other risk factors, such as hypertension, visceral obesity or dyslipidemia, by focusing our attention on the relation between Acute Coronary Syndrome (ACS) and high HOMA index. Methods We evaluated glucose and insulin levels at baseline and post-prandial phase, in order to estimate HOMA index in both the conditions; we related the data obtained with the incidence of cardiovascular events, also investigating traditional cardiovascular risk factors. The cohort included 118 patients with a clinical diagnosis of ACS and excluded those with type 1 diabetes, acute inflammatory diseases, hepatic or renal failure, disreactive disorders, autoimmunity and cancer. Subjects Subjects were followed-up for a period of 1 year, being subdivided in three groups: (1) subjects at elevated HOMA (HOMA ≥6); (2) subjects at intermediate HOMA (HOMA <6 and ≥2); (3) subjects at low HOMA (HOMA ≤2). We considered as end points new cardiovascular events, cerebrovascular events (both TIA and stroke), procedures of revascularization with angioplasty or surgery, cardiovascular death, sudden death. Results Patients with elevated HOMA have a higher incidence of previous cardio- and cerebrovascular events ( p = 0.03), myocardial infarction without ST elevation ( p = 0.005), unstable angina ( p = 0.01), asymptomatic carotid plaques ( p = 0.05), depressed systolic function ( p = 0.05); we found, also, a significant statistic correlation between HOMA index and high levels of CRP, fibrinogen, serum creatinine and TnI. Cardiovascular and cerebrovascular events were registered in 61% of patients with elevated HOMA during the follow up, despite of 25% registered in the control group: so we could consider HOMA index as a negative prognostic variable, also in virtue by the statistic correlation with the inflammatory markers, whose power of prediction is already known. Conclusions Beyond traditional cardiovascular risk factors, insulin resistance quantified by HOMA index seems to significantly have an important prognostic role, both in primary and secondary prevention in patients with Acute Coronary Syndrome.