The influence of weight excess on the postprandial lipemia in adolescents

Dyslipidemia in childhood and adolescence: from screening to management

PURPOSE OF REVIEW

To summarize types of dyslipidemia frequently encountered during childhood and adolescence, with a focus on screening, diagnosis, and management.

RECENT FINDINGS

It is important that screening for atherosclerotic cardiovascular disease (ASCVD) begin in childhood. Genetic testing allows for increased awareness of dyslipidemia and more targeted intervention. Pharmacologic treatment of pediatric dyslipidemias has a good safety profile and can reduce adult ASCVD risk.

SUMMARY

Much of what is known about pediatric dyslipidemia has been extrapolated from adult data, but recently, there have been increasing investigations within the pediatric population to better guide diagnosis and management of these disorders.

Postprandial Dyslipidemia, Hyperinsulinemia, and Impaired Gut Peptides/Bile Acids in Adolescents with Obesity

BACKGROUND

With increased rates of obesity and insulin resistance in youth, development of postprandial dyslipidemia, an important cardiovascular disease risk factor, is a concern. Glucagon-like peptides (ie, GLP-1 and GLP-2) and bile acids have been shown to regulate dietary fat absorption and postprandial lipids in animal models and humans. We hypothesize that the physiological response of GLPs and bile acids to dietary fat ingestion is impaired in adolescents with obesity and this associates with marked postprandial dyslipidemia and insulin resistance.

METHODS

In this cross-sectional study, normal weight adolescents and adolescents with obesity underwent a 6-hour oral fat tolerance test. The postprandial lipoprotein phenotype profile was determined using various assays, including nuclear magnetic resonance spectroscopy, to characterize lipoprotein particle number, size, lipid content, and apolipoproteins. GLP-1 and GLP-2 were quantified by electrochemiluminescent immunoassays. Total bile acids were measured by an automated enzymatic cycling colorimetric method and the bile acid profile by mass spectrometry.

RESULTS

Adolescents with obesity exhibited fasting and postprandial dyslipidemia, particularly augmented postprandial excursion of large triglyceride-rich lipoproteins. Postprandial GLPs were reduced and inversely correlated with postprandial dyslipidemia and insulin resistance. Postprandial bile acids were also diminished, particularly lithocholic acid, a potent stimulator of GLP-1 secretion.

CONCLUSION

Blunted postprandial GLP and bile acid response to dietary fat ingestion strongly associates with marked postprandial dyslipidemia. Further investigation is needed to assess their potential utility as early biomarkers for postprandial dyslipidemia in adolescents with obesity.

Postprandial dyslipidemia in insulin resistant states in adolescent populations

Obesity and the metabolic syndrome are becoming increasingly prevalent not only in adults, but also in adolescents. The metabolic syndrome, a complex cluster of metabolic abnormalities, increases one's risk of developing type 2 diabetes and cardiovascular disease (CVD). Dyslipidemia, a key component of the metabolic syndrome, is highly associated with insulin resistance and contributes to increased CVD risk. Dyslipidemia has traditionally been assessed using a fasting lipid profile [i.e. fasting triglycerides, total cholesterol, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C)]. However, the postprandial state predominates over the course of a day and non-fasting triglycerides independently predict CVD risk. In insulin resistant states, the intestine overproduces triglyceride-rich lipoprotein (TRL) particles, termed chylomicrons (CMs), following ingestion of a fat-containing meal, as well as in the fasting state. Along with elevated hepatic TRLs (i.e. very-low density lipoproteins), CMs contribute to remnant lipoprotein accumulation, small dense LDL particles, and reduced HDL-C, which collectively increase CVD risk. Given the early genesis of atherosclerosis and physiological metabolic changes during adolescence, studying postprandial dyslipidemia in the adolescent population is an important area of study. Postprandial dyslipidemia in the pediatric population poses a significant public health concern, warranting a better understanding of its pathogenesis and association with insulin resistance and CVD. This review discusses the metabolic syndrome, focusing on the link between insulin resistance, postprandial dyslipidemia, and CVD risk. Furthermore, the clinical significance and functional assessment of postprandial dyslipidemia, specifically in the adolescent population, is discussed in more detail.

Lipid profiles in French West Indies sickle cell disease cohorts, and their general population

BACKGROUND

The pathophysiology of sickle cell disease (SCD) and the variability of its clinical expression remain not fully understood, whether within or between different SCD genotypes. Recent studies have reported associations between lipid levels and several SCD complications. If lipid levels have been previously described as low in sickle cell anemia (SCA), few data have been provided for sickle cell SC disease (SCC). We designed our epidemiological study to isolate lipid levels and profiles by genotype in Guadeloupian cohorts of SCA and SCC adult patients, at steady state. We compared SCD lipid levels with those of the Guadeloupian general population (GGP), and analyzed potential associations between lipid levels and SCD complications (vaso-occlusive crises, acute chest syndrome and osteonecrosis).

METHODS

Lipids, apolipoproteins, biological variables and anthropometric evaluation, were collected at steady state from medical files for 62 SCC and 97 SCA adult patients. Clinical SCD complications were collected from the clinical files. Analysis was conducted by genotype for all variables.

RESULTS

Different SCC and SCA lipid profiles, both distinct from their GGP's, were identified. Compared to SCC and GGP, higher triglyceride (TG) levels were observed in SCA patients, independent of hydroxyurea, hemolysis, gender, age, body mass index (BMI), abdominal obesity and clinical nutritional status. Our survey highlights also subsequent anthropometrical phenotypes, with an over-representation of abdominal obesity with normal BMI in SCA patients, and affecting almost exclusively females in both genotypes. Moreover, more frequent positive history of acute chest syndrome (ACS) was observed in SCA patients with TG level higher than 1.50 g/l, and of osteonecrosis in SCC patients having non high-density lipoprotein-cholesterol level (Non HDL-C) higher than 1.30 g/l.

CONCLUSIONS

This study reveals that SCA and SCC patients exhibit distinct lipid profiles and suggests that high TG and Non HDL-C levels are associated with past histories of ACS and osteonecrosis in SCA and SCC patients, respectively.

Postprandial Dyslipidemia: Pathophysiology and Cardiovascular Disease Risk Assessment

Although the fed state predominates over the course of a day, the fasting lipid profile has traditionally been used to assess cardiovascular disease (CVD) risk. The nonfasting lipid profile may be more reflective of the daily circulating plasma lipids and simplifies lipid monitoring for patients, laboratories, and clinicians. Nonfasting triglyceride levels are also independently associated with cardiovascular events, leading to several clinical guidelines (e.g. in Denmark, the UK, Europe, and Canada) now recommending nonfasting lipid testing in the primary prevention setting. Obese and insulin resistant states are associated with intestinal chylomicron overproduction and subsequent remnant lipoprotein accumulation, leading to development of postprandial dyslipidemia in the fed state. Postprandial dyslipidemia is thought to be a major contributor of atherogenesis and shown to be an important CVD risk factor. As intestinal peptides (e.g. glucagon-like-peptide 1; GLP-1) have been shown to regulate chylomicron output, alterations in these signaling pathways in insulin resistant states may play a role in the development and/or progression of postprandial dyslipidemia. Although several advances have been made in understanding postprandial dyslipidemia in insulin resistance and its association with CVD, several limitations remain. Although nonfasting lipid measurements (i.e. random blood sampling) are now recommended in some countries, a more functional assessment of postprandial lipemia involves ingestion of a high-fat meal with subsequent blood collection over a specified time period (i.e. oral fat tolerance test). However, oral fat tolerance test methodology remains largely unstandardized and reference values to interpret postprandial values remain to be accurately established. Development of standardized methodologies and biomarker profiles for assessment of postprandial dyslipidemia in clinical practice will enable early and accurate identification of those at risk for CVD.

Postprandial lipemia: factoring in lipemic response for ranking foods for their healthiness

One of the limitations for ranking foods and meals for healthiness on the basis of the glycaemic index (GI) is that the GI is subject to manipulation by addition of fat. Postprandial lipemia, defined as a rise in circulating triglyceride containing lipoproteins following consumption of a meal, has been recognised as a risk factor for the development of cardiovascular disease and other chronic diseases. Many non-modifiable factors (pathological conditions, genetic background, age, sex and menopausal status) and life-style factors (physical activity, smoking, alcohol and medication use, dietary choices) may modulate postprandial lipemia. The structure and the composition of a food or a meal consumed also plays an important role in the rate of postprandial appearance and clearance of triglycerides in the blood. However, a major difficulty in grading foods, meals and diets according to their potential to elevate postprandial triglyceride levels has been the lack of a standardised marker that takes into consideration both the general characteristics of the food and the food’s fat composition and quantity. The release rate of lipids from the food matrix during digestion also has an important role in determining the postprandial lipemic effects of a food product. This article reviews the factors that have been shown to influence postprandial lipemia with a view to develop a novel index for ranking foods according to their healthiness. This index should take into consideration not only the glycaemic but also lipemic responses.

Effects of the n-6/n-3 polyunsaturated fatty acids ratio on postprandial metabolism in hypertriacylglycerolemia patients

Background

Atherosclerosis is a postprandial phenomenon. The balanced n-6/n-3 PUFA ratio contributing to the prevention of atherosclerosis has been well shown, but the effect of the ratio on postprandial metabolism has not been fully investigated. The aim of this study was to investigate the effects of the n-6/n-3 PUFAs ratio on postprandial metabolism in hypertriacylglycerolemia patients, comparing them to healthy controls.

Methods

Test meals with 0.97 (high n-3) and 8.80 (low n-3) n-6/n-3 PUFAs ratio were administered in a randomized crossover design to 8 healthy and 8 hypertriacylglycerolemia subjects. Blood samples were collected for 8 hours after meals to measure triglyceride (TG), total cholesterol (TC), HDL, ApoA, ApoB, glucose, insulin, inflammatory makers including tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), endothelial function including nitric oxide (NO) and endothelin-1 (ET-1).

Results

According to repeated–measures ANOVA, the postprandial response of lipid, glucose, insulin, inflammation and endothelial function were not significantly different between meals. The postprandial TG and NO response were significantly different between healthy control (HC) and hypertriglyceridemia group (HTG) after both meals (P < 0.01). After both meals maximal change and iAUC for TG was all higher in HTG group than HC group, the difference was significant after low n-3 meal but not after high n-3 meal. The concentration of glucose, insulin, IL-6, TNFα and ET-1 at each time point was higher and NO was lower in HTG group, but the maximal change and iAUC had no significant difference except for iAUC of insulin, IL-6 and diAUC of NO after low n-3 meal.

Conclusions

The ratio of n-6 and n-3 maybe do not acutely influence the postprandial metabolism, inflammatory response and endothelial function, but the low n-3 meal can strengthen the difference between HTG and HC group.