Plasma Chylomicrons Research Articles

Effects of Age and Diet on Triglyceride Metabolism in Mice.

Both age and diet can contribute to alterations in triglyceride metabolism and subsequent metabolic disease. In humans, plasma triglyceride levels increase with age. Diets high in saturated fats can increase triglyceride levels while diets high in omega-3 fatty acids decrease triglyceride levels. Here we asked how age and long-term diet effected triglyceride metabolism in mice. We fed male and female mice a low-fat diet, a western diet, or a diet high in polyunsaturated and omega-3 (n-3) fatty acids for up to 2 years. We measured survival, body composition, plasma triglyceride levels, chylomicron clearance, and oral fat, glucose, and insulin tolerance. Triglyceride levels in mice did not increase with age, regardless of diet. Oral fat tolerance increased with age, while chylomicron clearance remained unchanged. Mice fed western diet had decreased survival. Interestingly, mice fed the n-3 diet gained more lean mass, and had lower insulin levels than mice fed either low-fat or western diet. Moreover, triglyceride uptake into the hearts of mice fed the n-3 diet was strikingly higher than in other groups. In mice, age-induced changes in triglyceride metabolism did not match those in humans. Our data suggested that mice, like humans, had decreased fat absorption with age, but plasma triglyceride clearance did not decrease with age in mice, resulting in lower plasma triglyceride levels and improved oral fat tolerance with age. A chronic diet high in n-3 fatty acids increased insulin sensitivity and uptake of triglycerides specifically into the heart but how these observations are connected is unclear. The changes in triglyceride metabolism that occur with age in humans are not reflected in a mouse model, thus mice are likely not an ideal model for understanding how age impacts lipid metabolism and subsequent metabolic disease.A fish-oil based high-fat diet high in omega-3 fatty acids significantly increases fatty acid uptake in the heart while at the same time decreases fasting insulin levels.In future studies it will be important to understand how the omega-3 fatty acid induced increase in fatty acid uptake affects cardiac function and how it is related to other phenotypes induced by omega-3 fatty acids.

Enterocyte-specific FATP4 deficiency elevates blood lipids via a shift from polar to neutral lipids in distal intestine.

Fatty acid transport protein (FATP)4 was thought to mediate intestinal lipid absorption, which was disputed by a study using keratinocyte-Fatp4-rescued Fatp4-/- mice. These knockouts when fed with a Western diet showed elevated intestinal triglyceride (TG) and fatty acid levels. To investigate a possible role of FATP4 on intestinal lipid processing, ent-Fatp4 (KO) mice were generated by Villin-Cre-specific inactivation of the Fatp4 gene. We aimed to measure circulating and intestinal lipids in control and KO mice after acute or chronic fat intake or during aging. Remarkably, ent-Fatp4 mice displayed an approximately 30% decrease in ileal behenic, lignoceric, and nervonic acids, ceramides containing these FA, as well as, ileal sphingomyelin, phosphatidylcholine, and phosphatidylinositol levels. Such decreases were concomitant with an increase in jejunal cholesterol ester. After a 2-wk recovery from high lipid overload by tyloxapol and oral-lipid treatment, ent-Fatp4 mice showed an increase in plasma TG and chylomicrons. Upon overnight fasting followed by an oral fat meal, ent-Fatp4 mice showed an increase in plasma TG-rich lipoproteins and the particle number of chylomicrons and very low-density lipoproteins. During aging or after feeding with a high-fat high-cholesterol (HFHC) diet, ent-Fatp4 mice showed an increase in plasma TG, fatty acids, glycerol, and lipoproteins as well as intestinal lipids. HFHC-fed KO mice displayed an increase in body weight, the number of lipid droplets with larger sizes in the ileum, concomitant with a decrease in ileal ceramides and phosphatidylcholine. Thus, enterocyte FATP4 deficiency led to a metabolic shift from polar to neutral lipids in distal intestine rendering an increase in plasma lipids and lipoproteins.NEW & NOTEWORTHY Enterocyte-specific Fatp4 deficiency in mice increased intestinal lipid absorption with elevation of blood lipids during fasting and aging, as well as after an acute oral fat-loading or chronic HFHC feeding. Lipidomics revealed that knockout mice displayed a shift from very long-chain to long-chain fatty acids, and from polar to neutral lipids, predominantly in the ileum. Thus, FATP4 may have a physiological function in the control of blood lipids via metabolic shifts in distal intestine.

The early effects of sleeve gastrectomy on postprandial chylomicron triglycerides during the progression of type 2 diabetes

BackgroundIt remains unclear whether early sleeve gastrectomy (SG) improves postprandial very-low-density lipoprotein (VLDL) as well as chylomicron triglycerides (TGs) in a weight-independent manner in patients with or without type 2 diabetes (DM). Herein we investigated the early effects of SG on postprandial VLDL and chylomicron kinetics. MethodsA liquid meal test was performed before and after 1 week of SG. The plasma was collected for postprandial triglyceride-rich lipoprotein kinetics analyses, including VLDLs and chylomicrons, isolated by high-speed ultracentrifugation. Lipidomics and metabolomics were used to profile lipid and metabolite compositions of plasma and postprandial chylomicrons. De novo fatty acid synthesis in intestinal epithelial cells treated with chylomicron metabolites was examined using RT-PCR, immunoblotting, and free fatty acid measurement. ResultsWe found that patients with DM had markedly higher VLDL TGs than patients without DM, and such an increase was still retained after SG. In contrast, SG significantly decreased postprandial chylomicron TGs, but surprisingly, the degree of the reduction in patients with DM was less prominent than in patients without DM, confirmed by untargeted lipidomics analysis. Moreover, 5 unique metabolites potentially linked to de novo fatty acid synthesis from the pathway analysis were discovered by further metabolomic analysis of postprandial chylomicrons from patients with DM who underwent SG and verified by In vitro intestinal epithelial cell culture experiments. ConclusionsSG in 1 week did not impact postprandial VLDL but decreased chylomicron TGs. Patients with DM keep higher postprandial chylomicron TG concentrations than patients without it after SG, potentially through some unique metabolites that increase intestinal fatty acid synthesis. These results implicate the timing for SG to reach lower intestinal fatty acid synthesis and postprandial chylomicron TG production is prior to the diagnosis of DM to potentially reduce cardiovascular risks.

A Combination of Single-Nucleotide Polymorphisms Is Associated with Interindividual Variability in Cholecalciferol Bioavailability in Healthy Men

Background: Most people require dietary vitamin D to achieve the recommended concentration of 25-hydroxyvitamin D [25(OH)D] in the blood. However, the response to vitamin D supplementation is highly variable among individuals.Objective: We assessed whether the variability in cholecalciferol bioavailability was associated with single-nucleotide polymorphisms (SNPs) in candidate genes.Methods: In a single-group design, 39 healthy adult men with a mean ± SD age of 33 ± 2 y and mean ± SD body mass index (in kg/m2) of 22.9 ± 0.3 were genotyped with the use of whole-genome microarrays. After an overnight fast, plasma 25(OH)D status was measured, and the subjects then consumed a meal that provided 5 mg cholecalciferol as a supplement. Plasma chylomicron cholecalciferol concentration was measured over 8 h, and cholecalciferol response was assessed by calculating the postprandial area under the curve. Partial least squares regression was used to test the association of SNPs in or near candidate genes (61 genes representing 3791 SNPs) with the postprandial cholecalciferol response.Results: The postprandial chylomicron cholecalciferol concentration peaked at 5.4 h. The cholecalciferol response was extremely variable among individuals (CV: 47%). It correlated with the chylomicron triglyceride (TG) response (r = 0.60; P < 0.001) but not with the fasting plasma 25(OH)D concentration (r = 0.04; P = 0.83). A significant (P = 1.32 × 10−4) partial least squares regression model that included 17 SNPs in 13 genes (including 5 that have been associated with chylomicron TG response) was associated with the variance in the cholecalciferol response.Conclusion: In healthy men, there is a high interindividual variability in cholecalciferol bioavailability that is associated with a combination of SNPs located in or near genes involved in both vitamin D and lipid metabolism. This trial was registered at clinicaltrials.gov as NCT02100774.

Role of circulating sphingolipids in lipid metabolism: Why dietary lipids matter.

Sphingolipids are structural components of cell membranes and lipoproteins but also act as signaling molecules in many pathophysiological processes. Although sphingolipids comprise a small part of the plasma lipidome, some plasma sphingolipids are recognized as implicated in the development of metabolic diseases and cardiovascular diseases. Plasma sphingolipids are mostly carried out into lipoproteins and may modulate their functional properties. Lipids ingested from the diet contribute to the plasma lipid pool besides lipids produced by the liver and released from the adipose tissue. Depending on their source, quality and quantity, dietary lipids may modulate sphingolipids both in plasma and lipoproteins. A few human dietary intervention studies investigated the impact of dietary lipids on circulating sphingolipids and lipid-related cardiovascular risk markers. On the one hand, dietary saturated fatty acids, mainly palmitic acid, may increase ceramide concentrations in plasma, triglyceride-rich lipoproteins and HDL. On the other hand, milk polar lipids may decrease some molecular species of sphingomyelins and ceramides in plasma and intestine-derived chylomicrons. Altogether, different dietary fatty acids and lipid species can modulate circulating sphingolipids vehicled by postprandial lipoproteins, which should be part of future nutritional strategies for prevention of cardiovascular diseases.

Glucagon-like Peptide-2 Acutely Enhances Chylomicron Secretion in Humans Without Mobilizing Cytoplasmic Lipid Droplets.

A portion of ingested fats are retained in the intestine for many hours before they are mobilized and secreted in chylomicron (CM) particles. Factors such as glucagon-like peptide-2 (GLP-2) and glucose can mobilize these stored intestinal lipids and enhance CM secretion. We have recently demonstrated in rodents that GLP-2 acutely enhances CM secretion by mechanisms that do not involve the canonical CM synthetic assembly and secretory pathways. To further investigate the mechanism of GLP-2's potent intestinal lipid mobilizing effect, we examined intracellular cytoplasmic lipid droplets (CLDs) in intestinal biopsies of humans administered GLP-2 or placebo. A single dose of placebo or GLP-2 was administered subcutaneously 5 hours after ingesting a high-fat bolus. In 1 subset of participants, plasma samples were collected to quantify lipid and lipoprotein concentrations for 3 hours after placebo or GLP-2. In another subset, a duodenal biopsy was obtained 1-hour after placebo or GLP-2 administration for transmission electron microscopy and proteomic analysis. GLP-2 significantly increased plasma triglycerides by 46% (P = 0.009), mainly in CM-sized particles by 133% (P = 0.003), without reducing duodenal CLD size or number. Several proteins of interest were identified that require further investigation to elucidate their potential role in GLP-2-mediated CM secretion. Unlike glucose that mobilizes enterocyte CLDs and enhances CM secretion, GLP-2 acutely increased plasma CMs without significant mobilization of CLDs, supporting our previous findings that GLP-2 does not act directly on enterocytes to enhance CM secretion and most likely mobilizes secreted CMs in the lamina propria and lymphatics.

Low circulating PCSK9 levels in LPL homozygous children with chylomicronemia syndrome in a syrian refugee family in Lebanon.

Familial chylomicronemia syndrome is a rare autosomal recessive disorder of lipoprotein metabolism characterized by the presence of chylomicrons in fasting plasma and an important increase in plasma triglycerides (TG) levels that can exceed 22.58 mmol/l. The disease is associated with recurrent episodes of abdominal pain and pancreatitis, eruptive cutaneous xanthomatosis, lipemia retinalis, and hepatosplenomegaly. A consanguineous Syrian family who migrated to Lebanon was referred to our laboratory after perceiving familial chylomicronemia syndrome in two children. The LPL and PCSK9 genes were sequenced and plasma PCSK9 levels were measured. Sanger sequencing of the LPL gene revealed the presence of the p.(Val227Phe) pathogenic variant in exon 5 at the homozygous state in the two affected children, and at the heterozygous state in the other recruited family members. Interestingly, PCSK9 levels in homozygous carriers of the p.(Val227Phe) were ≈50% lower than those in heterozygous carriers of the variant (p-value = 0.13) and ranged between the 5th and the 7.5th percentile of PCSK9 levels in a sample of Lebanese children of approximately the same age group. Moreover, this is the first reported case of individuals carrying simultaneously an LPL pathogenic variant and PCSK9 variants, the L10 and L11 leucine insertion, which can lower and raise low-density lipoprotein cholesterol (LDL-C) levels respectively. TG levels fluctuated concomitantly between the two children, were especially high following the migration from a country to another, and were reduced under a low-fat diet. This case is crucial to raise public awareness on the risks of consanguineous marriages to decrease the emergence of inherited autosomal recessive diseases. It also highlights the importance of the early diagnosis and management of these diseases to prevent serious complications, such as recurrent pancreatitis in the case of familial hyperchylomicronemia.

Treatment of Type V dyslipoproteinemia: A rare phenotype of lipid disorders

Background and Aims : Despite Type IV (T4DL) and Type V (T5DL) dyslipidemia are both characterized by hypertriglyceridemia (HTG), T5DL is specifically characterized by a rare phenotype of lipid disorders and the presence of fasting plasma chylomicrons. The present study was aimed to report our experience on treatment of T5DL in a tertiary medical center.

Platycodi Radix Beverage Improves Postprandial Lipemic Response Associated With Plasma Bacteria-Derived Extracellular Vesicles in Healthy Adults With an Oral Fat Load

ObjectivesThis study aimed to examine the responsiveness of postprandial triglyceride-rich lipoprotein (TRL) metabolism to Platycodi radix beverage (PR) is associated with the alterations in plasma bacteria-derived extracellular vesicles (EVs) composition.MethodsNinety-six healthy and normolipidemic adults were randomly divided into two groups and consumed PR or placebo for 8 weeks. An oral fat tolerance test was performed before and after the 8-week intervention to access the postprandial lipid response. Plasma TG, chylomicron TG (CM-TG), and lipoprotein lipase (LPL) mass levels were measured at fasting, 3, and 6 hours during the oral fat tolerance test and summarized by computing the area under the curve (AUC). EVs isolated from fasting plasma samples were identified using 16S rRNA sequencing. A linear mixed-effect model was used to analyze the difference between the two groups. TLR clearance responder to PR consumption was defined by QUalitative INteraction Trees (QUINT). Lasso regularized generalized linear model (GLM) was used to find genera associated with the responsiveness.ResultsPR consumption for 8 weeks noticeably decreased AUC (0–3h) values for TG and CM-TG compared to the placebo group. Responders for TRL clearance were defined as subjects having higher LPL mass (150.6 ng/mL) and dietary fat intake (38.5 g/day) at baseline. Responders showed remarkable reductions in AUC (0–6h) values for TG and CM-TG in the PR group compared to the placebo group. Furthermore, GLM analysis demonstrated that the responsiveness of postprandial TRL clearance was accurately predicted by the model consisting of changes in the relative abundance of 16 genera, suggesting the close association between them.ConclusionsThese findings suggest that PR consumption modulates postprandial TRL clearance by altering plasma EV composition in normolipidemic adults with habitually higher fat intake over 38.5 g/day.Funding SourcesThis work was supported by the BK21 FOUR (Fostering Outstanding Universities for Research) funded by the Ministry of Education (MOE, Korea) and National Research Foundation of Korea (NRF), and the Bio & Medical Technology Development Program of the National Research Foundation (NRF), funded by the Ministry of Science & ICT (2012M3A9C4048761).

Current Diagnosis and Management of Primary Chylomicronemia

Primary chylomicronemia (PCM) is a rare and intractable disease characterized by marked accumulation of chylomicrons in plasma. The levels of plasma triglycerides (TGs) typically range from 1,000 - 15,000 mg/dL or higher. PCM is caused by defects in the lipoprotein lipase (LPL) pathway due to genetic mutations, autoantibodies, or unidentified causes. The monogenic type is typically inherited as an autosomal recessive trait with loss-of-function mutations in LPL pathway genes ( LPL , LMF1 , GPIHBP1 , APOC2 , and APOA5 ). Secondary/environmental factors (diabetes, alcohol intake, pregnancy, etc.) often exacerbate hypertriglyceridemia (HTG). The signs, symptoms, and complications of chylomicronemia include eruptive xanthomas, lipemia retinalis, hepatosplenomegaly, and acute pancreatitis with onset as early as in infancy. Acute pancreatitis can be fatal and recurrent episodes of abdominal pain may lead to dietary fat intolerance and failure to thrive.The main goal of treatment is to prevent acute pancreatitis by reducing plasma TG levels to at least less than 500-1,000 mg/dL. However, current TG-lowering medications are generally ineffective for PCM. The only other treatment options are modulation of secondary/environmental factors. Most patients need strict dietary fat restriction, which is often difficult to maintain and likely affects their quality of life.Timely diagnosis is critical for the best prognosis with currently available management, but PCM is often misdiagnosed and undertreated. The aim of this review is firstly to summarize the pathogenesis, signs, symptoms, diagnosis, and management of PCM, and secondly to propose simple diagnostic criteria that can be readily translated into general clinical practice to improve the diagnostic rate of PCM. In fact, these criteria are currently used to define eligibility to receive social support from the Japanese government for PCM as a rare and intractable disease.Nevertheless, further research to unravel the molecular pathogenesis and develop effective therapeutic modalities is warranted. Nationwide registry research on PCM is currently ongoing in Japan with the aim of better understanding the disease burden as well as the unmet needs of this life-threatening disease with poor therapeutic options.

Deletion of P110δ promotes the development of myocarditis in ApoE‑deficient mice by increasing mononuclear cell peritoneal infiltration.

Phosphoinositide 3-kinase catalytic subunit δ isoform (P110δ) is mainly expressed in white blood cells. It is involved in T and B lymphocyte differentiation, maturation and the neutrophil chemotaxis process. Apolipoprotein E (ApoE) is an arginine-rich alkaline protein, which is present in plasma chylomicron, low-density lipoprotein and very low-density lipoprotein. The present study aimed to determine the effects of P110δ deletion on myocarditis in ApoE−/− mice. A mouse model of ApoE and P110δ double deletion was initially constructed; hematoxylin and eosin (H&E) staining was performed to detect the histological alterations in the mouse myocardium. Systolic and diastolic alterations, and alterations in the left ventricular fractional shortening (LVFS) and left ventricular ejection fraction (LVEF) were examined by electrocardiogram. Blood cell of ApoE and P110δ double mice was used to detect changes in white blood cells and monocytes. Western blotting was used to detect the expression levels of apoptosis-associated proteins, whereas flow cytometry was used to detect the percentage of apoptosis. Morphological alterations in myocardial cells were observed under a microscope. The results of polymerase chain reaction demonstrated that double deletion mice were successfully constructed. H&E staining revealed that cells in the ApoE−/− mice were spindle-shaped; however, the nuclei were smaller in the double deletion mice. There was no change in cardiac contraction in normal mice; however, in double deletion mice, the systolic and diastolic contractions were markedly reduced. LVFS and LVEF were decreased compared with in the control group. Blood cell analysis indicated that the content of white blood cells and monocytes in the experimental group was significantly higher than that in the control group. Western blotting demonstrated that the expression levels of apoptotic proteins in double deletion mice were significantly higher compared with in the control group. Flow cytometry revealed that the apoptotic ratio was increased in double deletion mice compared with in the control group (42 vs. 21%). These findings suggested that deletion of P110δ may induce monocyte peritoneal infiltration and increase apoptosis, thus promoting the development of myocarditis.

A Rare Disease of Familial Chylomicronemia Syndrome in a 20 Days Infant

Familial chylomicronemia syndrome is a group of very rare genetic disorders. It is inherited as autosomal recessive disorder. Its estimated incidence is 1 in 1000000 populations, characterized by deficient activity of an enzyme lipoprotein lipase (LPL) or apo-protein C-II, resulting into severe fasting hypertriglyceridemia and massive accumulations of chylomicrons in plasma. LPL deficiency typically presents in childhood with failure to thrive, colicky abdominal pain, eruptive xanthomas, lipemiaretinalis, pancreatitis and hepatomegaly. We are reporting a rare case of familial chylomicronemia in a 20 days old child who was presented with pneumonia, his plasma incidentally found like milk during routine collection of his blood sample. As the child was only 20 days old with very high triglyceride level, so breast feeding continued and cocktail therapy with low dose Tablet Fenofibrate, Tablet Niacin, Tablet Atovastatin started after referral to paediatric cardiologist at 3 months of age.&#x0D; Journal of Armed Forces Medical College Bangladesh Vol.15 (1) 2019: 107-109

Validation of a Method for Estimating Vitamin A Absorption Efficiency Based on Compartmental Analysis of Post-Prandial Plasma Retinyl Ester Kinetics

Abstract Objectives Because good methods are not available to estimate vitamin A (VA) absorption, we evaluated an approach based on modeling retinyl ester response to an oral VA dose. Methods We generated data for 12 theoretical subjects, assigning values for VA absorption, stores, and kinetic parameters; we used WinSAAM (Simulation, Analysis and Modeling software) to simulate data (without and with 5% average error) for plasma chylomicron retinyl esters (RE) and retinol versus time (30 min to 8 h or 56 d, respectively) after ingestion of labeled VA; next we fit data to a previously-published 9-component model for VA metabolism to obtain “known” values for VA absorption. Then RE data only were modeled for each subject using a robust (n = 16 times) vs truncated sampling schedule (n = 10) and model-predicted absorptions were compared to known values. Areas under the plasma RE response curves (AUCs) were also calculated and compared to known absorption values. Results Known values for VA absorption based on modeling all data with error ranged from 54 – 92% (mean, 72%), VA stores from 160 – 1775 μmol, and chylomicron t1/2 from 6 – 12 min. Using the full sampling scheme for RE, the ratio of model-predicted to known absorption ranged from 0.927 – 1.06 (mean, 0.997); using the truncated scheme, the ratio was 0.814 – 1.13 (mean, 0.973). AUCs were not significantly correlated with known values for VA absorption (R2 = 0.112; P &amp;gt; 0.05), presumably because absorption and chylomicron catabolism are occurring simultaneously. Conclusions By modeling chylomicron RE tracer data after ingestion of labeled VA, absorption efficiency was estimated accurately using error-free data; using data with 5% error, estimates were within 10% of known values (full sampling) or within 20% (truncated). If subjects, after an overnight fast, consume a breakfast containing some fat and a known amount of VA, then no tracer is required to estimate VA absorption using this modeling approach. By incorporating a population-based design, the method could be used in children. Funding Sources Supported by Bill &amp; Melinda Gates Foundation (Project Number OPP1115464) and HarvestPlus (BH183438).

Effects of gastric bypass surgery on postprandial gut and systemic lipid handling

Obesity is often associated with increased postprandial triglyceride (TG) concentrations, mainly from chylomicrons- and VLDL-TG. These alterations are usually reverted to normal after gastric bypass surgery (GB), through mechanisms which remain unknown. The objective of this study was therefore to assess the contribution of exogenous labelled fatty acids ingested with a meal to postprandial blood chylomicrons and VLDL-TG concentrations after GB. 7GB patients 3-5 years after surgery (GB: 2M/5F, mean BMI 30±2kg/m2, mean age 40±3 years), 6 overweight non operated subjects (OW: 1M/5F, mean BMI 31±3kg/m2, mean age 38±2 years) and 8 normal weight healthy subjects (NW: 4M/4F, mean BMI 22±1kg/m2, mean age 26±4 years) were studied over 7h following ingestion of a liquid meal containing 18g fat labelled with 250mg 13C16 palmitate, 22g protein, 36g fructose and 36g glucose. TG, 13C palmitate (13C-palm) and apoB48 concentrations were measured hourly in whole plasma and/or in chylomicrons and VLDL lipoprotein sub-fractions. OW subjects had higher chylomicron-than NW (chylo-TG 96.5 (23.1) vs 28.8 (11.8) mmol/l*420min (p=0.02)), but similar total, chylo-13C-palm and apoB48 iAUCs. In GB, chylo- 13C-palm and apoB48 increased earlier after meal ingestion, but then remained lower than in NW and OW throughout the postprandial period. GB also had lower chylo-TG iAUCs than OW (8.9 (11.5) vs 96.5 (23.2) mmol/l*420min, p=0.003). Their apoB48 iAUCs were not different from NW and OW (509.2 (90.5) vs 710.2 (80.5) and 870.1 (297.6) pg/ml*420min, all p>0.05). An accelerated postprandial apoB48 rise, together with unchanged postprandial apoB48 iUAC, suggests that intestinal fat absorption and chylomicron secretion was quantitatively unaltered, but accelerated after gastric bypass. In contrast, the decreased postprandial chylo-TG and 13C-palm iAUCs suggest that plasma chylomicron clearance was enhanced after gastric bypass.

The Association of Polyunsaturated Fatty Acid δ-5-Desaturase Activity with Risk Factors for Type 2 Diabetes Is Dependent on Plasma ApoB-Lipoproteins in Overweight and Obese Adults

δ-5 and δ-6 desaturases (D5D and D6D) catalyze the endogenous conversion of n-3 (ω-3) and n-6 (ω-6) polyunsaturated fatty acids (PUFAs). Their activities are negatively and positively associated with type 2 diabetes (T2D), respectively, by unclear mechanisms. Elevated plasma apoB-lipoproteins (measured as plasma apoB), which can be reduced by n-3 PUFA intake, promote T2D risk factors. The aim of this study was to test the hypothesis that the association of D5D and D6D activities with T2D risk factors is dependent on plasma apoB. This is a pooled analysis of 2 populations recruited for 2 different metabolic studies. It is a post hoc analysis of baseline data of these subjects [n=98; 60% women (postmenopausal); mean ± SD body mass index (in kg/m2): 32.8±4.7; mean ± SD age: 57.6±6.3 y]. Glucose-induced insulin secretion (GIIS) and insulin sensitivity (IS) were measured using Botnia clamps. Plasma clearance of a high-fat meal (600 kcal/m2, 66% fat) and white adipose tissue (WAT) function (storage of 3H-triolein-labeled substrate) were assessed in a subpopulation (n=47). Desaturase activities were estimated from plasma phospholipid fatty acids. Associations were examined using Pearson and partial correlations. While both desaturase activities were positively associated with percentage of eicosapentaenoic acid, only D5D was negatively associated with plasma apoB (r=-0.30, P=0.003). Association of D5D activity with second-phase GIIS (r=-0.23, P=0.029), IS (r=0.33, P=0.015, in women) and 6-h area-under-the-curve (AUC6h) of plasma chylomicrons (apoB48, r=-0.47, P=0.020, in women) was independent of age and adiposity, but was eliminated after adjustment for plasma apoB. D6D activity was associated in the opposite direction with GIIS (r=0.24, P=0.049), IS (r=-0.36, P=0.004) and AUC6h chylomicrons (r=0.52, P=0.004), independent of plasma apoB. Both desaturases were associated with plasma interleukin-1-receptor antagonist (D5D: r=-0.45, P<0.001 in women; D6D: r=-0.33, P=0.007) and WAT function (trend for D5D: r=0.30, P=0.05; D6D: r=0.39, P=0.027) independent of any adjustment. Association of D5D activity with IS, lower GIIS, and plasma chylomicron clearance is dependent on plasma apoB in overweight and obese adults.

Familial chylomicronemia syndrome: Bringing to life dietary recommendations throughout the life span

Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive disorder with loss of function mutations of lipoprotein lipase resulting in hypertriglyceridemia and accumulation of chylomicrons in plasma, often leading to acute pancreatitis. The mainstay of treatment is a specialized very-low-fat diet. Even adhering to the diet, some patients may experience high triglycerides and pancreatitis. There currently are no comprehensive dietary guidelines. To report best practices and develop comprehensive dietary guidelines for nutrition therapy in patients with FCS. Registered dietitian nutritionists (RDNs) convened to develop this report based on experience treating patients with FCS and a review of current literature on the topic. One author provided a patient perspective of living with FCS. This report provides guidelines and rationales for nutrition therapy associated with FCS across the life span. The top global guidelines are to (1) limit fat to <15 to 20g per day (<10%-15% of total daily energy intake); (2) meet recommendations for essential fatty acids: α-linolenic acid and linoleic acid; (3) choose complex carbohydrate foods while limiting simple and refined carbohydrate foods; (4) supplement with fat-soluble vitamins, minerals, and medium-chain triglyceride oil, as needed; (5) adjust calories for weight management. Recommended foods include vegetables, whole grains, legumes, lean protein foods, fruits in limited amounts, and fat-free milk products without added sugars. Foods to avoid include alcohol and products high in sugar. These patient-centered nutrition guidelines provide guidance to help patients adhere to the recommended diet and optimize nutritional needs.

Primary intestinal lymphangiectasia in adults - diagnostic and therapeutic challenge

Introduction. Primary intestinal lymphangiectasia is a rare disorder, characterized by abnormal dilation of intestinal lymphatic vessels and extensive enteric loss of lymph rich in plasma proteins, lymphocytes and chylomicrons. The main characteristics of the disease are hypoalbuminemia, hypogammaglobulinemia, lymphocytopenia, and more rarely, the deficit of liposoluble vitamins and anemia. Except for primary, there are secondary lymphangiectasia, associated with celiac disease, malignant, infective and inflammatory diseases of the small intestine, fibrosis, liver and cardiovascular diseases. Case report. A male, 33 years of age, presented for his medical examination suffering from diarrhea and edema. The diagnosis was established upon the histological examination of a small intestine biopsy during double balloon enteroscopy, which revealed changes only in one segment of the intestine examined. Such a finding was later confirmed by the video endoscopy capsule. Conclusion. The diagnosis of intestinal lymphangiectasia is usually established before the age of 3, but it can also be diagnosed in adults. The diagnosis is based on the histological analysis of the intestinal mucosa biopsy, obtained by endoscopic procedures. The diagnosis of primary intestinal lymphangiectasia is also made upon the exclusion of secondary causes.

The burden of familial chylomicronemia syndrome from the patients’ perspective

ABSTRACTBackground: Familial chylomicronemia syndrome (FCS) is a rare, inherited lipid disorder characterized by high levels of plasma triglycerides and chylomicrons, which may cause life-threatening acute pancreatitis. Currently no FDA-approved treatment exists. Management is low-fat diet (<20g fat/day), which is difficult to maintain. With the restricted diet, triglycerides may remain elevated. We conducted discussions with patients and caregivers to better understand the burden of FCS from their perspectives.Methods: A panel of FCS patients and caregivers was assembled to discuss and assess the clinical and psychosocial burden of FCS.Results: Ten adults with FCS (median age 48 yr) and their spouses/caregivers were asked specific questions about their experiences living with FCS. Patients with FCS stated their symptoms were abdominal pain, nausea, diarrhea, constipation, bloating, and fatigue. Patients reported a median of 34 episodes of acute pancreatitis over their lifetimes; half of these led to hospitalizations, each with an average stay of 6.5 days. The psychosocial burden of FCS was primarily associated with the restricted diet, anxiety and stress of FCS.Conclusions: Living with FCS imposes a significant clinical and psychosocial burden on patients and caregivers, who reported reduced quality of life, limited employment opportunities, socialization and increased burden on family.

Dose‐response Effects of Soybean Oil in Salad Dressing upon the Bioavailability of Carotenoids/Fat‐soluble Vitamins in Salad Vegetables

Research is needed to quantify the dose effect between added vegetable oil and carotenoid/fat‐soluble vitamin absorption from vegetables. The objectives were to evaluate the dose‐response relation between the amount of soybean oil in salad dressing and the absorption of: 1) carotenoids, phylloquinone, and tocopherols in salad vegetables; 2) retinyl palmitate formed from the provitamin A carotenoids, α‐ and β‐carotene. Women (n = 12) each consumed 5 equivalent salads containing grated carrots, cherry tomatoes, romaine lettuce and spinach. The salads with salad dressings containing 0, 2, 4, 8, or 32 g phylloquinone‐ and tocopherol‐stripped soybean oil were consumed in randomly assigned order and separated by ≥ 2 wk. The plasma chylomicron fraction was isolated from blood samples collected at baseline and 2, 3.5, 5, 7, and 9.5 h postprandially. Across the entire 0 – 32 g range, the amount of soybean oil in salad dressing was linearly related to the plasma chylomicron area under the curve (AUC) values for α‐carotene, lycopene, phylloquinone, and retinyl palmitate. Across a more limited 0 – 8 g range of soybean oil, there was a linear increase in the chylomicron AUC values for β‐carotene. The absorption of all carotenoids and fat‐soluble vitamins was highest with 32 g ingested oil (P &lt; 0.002). For the carotenoids/fat‐soluble vitamins that showed a linear response, the slope β (soybean oil effect) varied widely between subjects. In conclusion, soybean oil in salad dressing promoted the absorption of all carotenoids and fat‐soluble vitamins from salad vegetables. For a large salad, maximal absorption required more than 8 g and up to 32 g or more of soybean oil. Linear models could be used to predict the relation between the amount of soybean oil and the absorption of α‐ and β‐carotene, lycopene, and phylloquinone, as well as that of the provitamin A conversion product, retinyl palmitate.Support or Funding InformationSupported by Unilever R&amp;D, Vlaardingen, the Netherlands

Modeling the dose effects of soybean oil in salad dressing on carotenoid and fat-soluble vitamin bioavailability in salad vegetables

Background: Previously, we showed that vegetable oil is necessary for carotenoid absorption from salad vegetables. Research is needed to better define the dose effect and its interindividual variation for carotenoids and fat-soluble vitamins.Objective: The objective was to model the dose-response relation between the amount of soybean oil in salad dressing and the absorption of 1) carotenoids, phylloquinone, and tocopherols in salad vegetables and 2) retinyl palmitate formed from the provitamin A carotenoids.Design: Women (n = 12) each consumed 5 vegetable salads with salad dressings containing 0, 2, 4, 8, or 32 g soybean oil. Blood was collected at selected time points. The outcome variables were the chylomicron carotenoid and fat-soluble vitamin area under the curve (AUC) and maximum content in the plasma chylomicron fraction (Cmax). The individual-specific and group-average dose-response relations were investigated by fitting linear mixed-effects random coefficient models.Results: Across the entire 0-32-g range, soybean oil was linearly related to the chylomicron AUC and Cmax values for α-carotene, lycopene, phylloquinone, and retinyl palmitate. Across 0-8 g of soybean oil, there was a linear increase in the chylomicron AUC and Cmax values for β-carotene. Across a more limited 0-4-g range of soybean oil, there were minor linear increases in the chylomicron AUC for lutein and α- and total tocopherol. Absorption of all carotenoids and fat-soluble vitamins was highest with 32 g oil (P < 0.002). For 32 g oil, the interindividual rank order of the chylomicron AUCs was consistent across the carotenoids and fat-soluble vitamins (P < 0.0001).Conclusions: Within the linear range, the average absorption of carotenoids and fat-soluble vitamins could be largely predicted by the soybean oil effect. However, the effect varied widely, and some individuals showed a negligible response. There was a global soybean oil effect such that those who absorbed more of one carotenoid and fat-soluble vitamin also tended to absorb more of the others. This trial was registered at clinicaltrials.gov as NCT02867488.