Exercise, postprandial triacylglyceridemia, and cardiovascular disease risk

Hypertriglyceridemia-induced acute pancreatitis in children: A mini-review

Severe hypertriglyceridemia (HTG) is a known metabolic cause of acute pancreatitis (AP) in pediatric patients. The incidence of hypertriglyceridemia-induced acute pancreatitis (HTG-AP) is less well established in pediatric compared to adult patients. Studies in adults suggest that higher risk of AP occurs when triglyceride levels (TG) are >1,000 mg/dL. Most common etiologies for severe HTG in pediatric patients are either from primary hypertriglyceridemia, underlying genetic disorders of lipid and TG metabolism, or secondary hypertriglyceridemia, separate disease or exposure which affects TG metabolism. Most common theories for the pathophysiology of HTG-AP include hydrolysis of TG by pancreatic lipase to free fatty acids leading to endothelial and acinar cell damage and ischemia, as well as hyperviscosity related to increased chylomicrons. Though there are varying reports of HTG-AP severity compared to other causes of AP, a steadily growing body of evidence suggests that HTG-AP can be associated with more severe course and complications. Therapeutic interventions for HTG-AP typically involve inpatient management with dietary restriction, intravenous fluids, and insulin; select patients may require plasmapheresis. Long term interventions generally include dietary modification, weight management, control of secondary causes, and/or antihyperlipidemic medications. Though some therapeutic approaches and algorithms exist for adult patients, evidence-based management guidelines have not been well established for pediatric patients.

L-arginine Improves Plasma Lipid Profile and Muscle Inflammatory Response in Trained Rats After High-Intense Exercise

Purpose: This study aimed to evaluate whether supplementation with L-arginine alone or in combination with physical exercise training can modulate rats' lipid and inflammatory profiles after a single intense exercise session. Methods: Male Wistar rats were divided into four different groups: control (C), trained (T), supplemented with L-arginine (C + A) and trained and supplemented (T + A). Animals from supplemented groups (C + A and T + A groups) received 300 mg/kg animal body weight L-arginine diluted in 30 mL of drinking water for 8 weeks. Exercise training protocol (moderate intensity-70% achieved in the maximum effort test) was held 5 days/week for 8 weeks. Results: Exercise training induced a decrease in the amount of plasma, cholesterol and triglyceride totals, and skeletal muscle VEGF and CINC. Supplementation alone showed a benefit by reducing LDL levels. Conclusion: Training combined with supplementation showed a pronounced reduction in skeletal muscle VEGF and CINC amount. L-arginine supplementation, especially when associated with the regular aerobic physical exercise at moderate intensity was able to improve not only plasma lipid profile but also the inflammatory response of skeletal muscle immediately after an exhaustive physical exercise session.

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.

Triglyceride Treatment in the Age of Cholesterol Reduction

Cholesterol reduction has markedly reduced major cardiovascular disease (CVD) events and shown regression of atherosclerosis in some studies. However, CVD has for decades also been associated with increased levels of circulating triglyceride (TG)-rich lipoproteins. Whether this is due to a direct toxic effect of these lipoproteins on arteries or whether this is merely an association is unresolved. More recent genetic analyses have linked genes that modulate TG metabolism with CVD. Moreover, analyses of subgroups of hypertriglyceridemic (HTG) subjects in clinical trials using fibric acid drugs have been interpreted as evidence that TG reduction reduces CVD events. This review will focus on how HTG might cause CVD, whether TG reduction makes a difference, what pathophysiological defects cause HTG, and what options are available for treatment.

Primary hypertriglyceridemia in children and adolescents

Primary disorders of lipid metabolism causing hypertriglyceridemia (HyperTG) result from genetic defects in triglyceride synthesis and metabolism. With the exception of lipoprotein lipase deficiency, these primary HyperTG disorders usually present in adulthood. However, some are unmasked earlier by precipitating factors, such as obesity and insulin resistance, and can be diagnosed in adolescence. Physical findings may be present and can include eruptive, palmer, or tuberoeruptive xanthomas. Triglyceride levels are very high to severe and can occur in the absence or the presence of other lipid abnormalities. Each of the causes of HyperTG is associated with an increased risk to develop recurrent pancreatitis and some may increase the risk of premature cardiovascular disease. Adoption of a healthy lifestyle that includes a low-fat diet, optimizing body weight, smoking avoidance/cessation, and daily physical activity is the first line of therapy. Pharmacologic therapies are available and can be beneficial in select disorders. Here, we review the causes of primary HyperTG in children and adolescents, discuss their clinical presentation and associated complications including the risk of pancreatitis and premature cardiovascular disease, and conclude with management and novel therapies currently in development. The goal of this article is to provide a useful resource for clinicians who may encounter primary HyperTG in the pediatric population.

Lipidomics: new insight into kidney disease

Due to the incidence of type-2 diabetes and hypertension, chronic kidney disease (CKD) has emerged as a major public health problem worldwide. CKD results in premature death from accelerated cardiovascular disease and various other complications. Early detection, careful monitoring of renal function, and response to therapeutic intervention are critical for prevention of CKD progression and its complications. Unfortunately, traditional biomarkers of renal function are insufficiently sensitive or specific to detect early stages of disease when therapeutic intervention is most effective. Therefore, more sensitive biomarkers of kidney disease are needed for early diagnosis, monitoring, and effective treatment. CKD results in profound changes in lipid and lipoprotein metabolism that, in turn, contribute to progression of CKD and its cardiovascular complications. Lipids and lipid-derived metabolites play diverse and critically important roles in the structure and function of cells, tissues, and biofluids. Lipidomics is a branch of metabolomics, which encompasses the global study of lipids and their biologic function in health and disease including identification of biomarkers for diagnosis, prognosis, prevention, and therapeutic response for various diseases. This review summarizes recent developments in lipidomics and its application to various kidney diseases including chronic glomerulonephritis, IgA nephropathy, chronic renal failure, renal cell carcinoma, diabetic nephropathy, and acute renal failure in clinical and experimental research. Analytical technologies, data analysis, as well as currently known metabolic biomarkers of kidney diseases are addressed. Future perspectives and potential limitations of lipidomics are discussed.

Effects of strength training on blood lipoprotein concentrations in postmenopausal women

Strength training is often identified as a contributing factor in prevention of diseases and as a non-pharmacological treatment for metabolic disorders and for control of body mass. Its protective effects and utility for management of disease are amplified in people at risk of diabetes mellitus and dyslipidemias, and cardiovascular diseases (CVD). Recently the benefits of strength training have been used to reduce the risk of these diseases emerging in postmenopausal women, who are at greater risk of CVD than men of the same age. Notwithstanding, little is known about the effects of strength training on metabolism of blood lipoproteins. The objective of this review was to compare the results of articles that have investigated the effects on lipoprotein concentrations of strength training in postmenopausal women. Current articles dealing with the subject, with publication dates from 1979 to 2012 and large numbers of citations by well-known researchers were identified on the Pubmed, Scopus and EBSCO databases. It was concluded that strength training possibly has an action that affects lipoprotein metabolism and concentrations in postmenopausal women.

Treatment options for hypertriglyceridemia: from risk reduction to pancreatitis

While there has been considerable focus on the role and treatment of LDL cholesterol levels, a definitive role of triglycerides in the management of cardiovascular disease has been uncertain. Notably, with increasing triglyceride levels, there is a parallel increase in cholesterol levels carried by triglyceride-rich lipoproteins, which has prompted interest in the use of non-HDL cholesterol levels as a tool guiding interventions. Recent studies have provided evidence for an independent role of triglyceride levels as a cardiovascular risk factor, and recently, an Endocrine Society guideline was published for treatment of hypertriglyceridemia. In contrast to the relative uncertainty regarding triglycerides and cardiovascular disease, a role of very high triglyceride levels as a risk factor for pancreatitis has been well known. The present paper summarizes the underlying evidence for a risk role for triglyceride levels in cardiovascular disease and pancreatitis, current treatment recommendations and areas of future research.

Resistance exercise at variable volume does not reduce postprandial lipemia in postmenopausal women

The aim of this study was to investigate the acute effects of resistance exercise sessions (RESs) performed at different levels of high-volume resistance exercise (HVRE) and low-volume resistance exercise (LVRE) on postprandial lipemia (PPL) in postmenopausal women. Thirty-nine healthy unconditioned postmenopausal women (59.5 ± 4.8 years of age, body mass 69.6 ± 9.1 kg, height 157.9 ± 7.2 cm, BMI 27.6 ± 4.1 kg m(-2), waist circumference 76.1 ± 9.7 cm, VO2max 18.7 ± 1.4 mL kg(-1) min(-1)) were assigned to a LVRE (n = 12), HVRE (n = 14), and control group (CG, n = 13). Experimental groups performed one RES involving eight exercises. The HVRE group performed three sets with a maximum of 15 repetitions, and the LVRE group performed one set with a maximum of 15 repetitions. Approximately 16 h after a RES, all of the groups were given an oral fat tolerance test (OFTT). During the RES, we evaluated the energy expenditure (EE) of the resistance session and excess postexercise oxygen consumption (EPOC); following the RES and the OFTT, we evaluated lipid profiles (total cholesterol, HDL, LDL, and triglycerides). While the study groups did not demonstrate significant differences in lipid profiles, the total energy expenditure (EE + EPOC) of the session exercise treatments was significantly higher for HVRE than for LVRE (0.60 ± 0.12 and 0.31 ± 0.11 MJ, respectively, p < 0.001). Different levels of resistance exercise do not lower basal triglyceride concentration and postprandial lipid profile parameters at approximately 16 h following resistance exercise in untrained postmenopausal women.

Resistant starch intake at breakfast affects postprandial responses in type 2 diabetics and enhances the glucose-dependent insulinotropic polypeptide – insulin relationship following a second meal

Resistant starch (RS) consumption can modulate postprandial metabolic responses, but its effects on carbohydrate (CHO) handling in type 2 diabetics (T2D) are unclear. It was hypothesized that a bagel high in RS would improve glucose and insulin homeostasis following the 1st meal, regardless of the amount of available CHO, and that in association with incretins, the effects would carry over to a 2nd meal. Using a randomized crossover design, 12 T2D ingested four different bagel treatments (their 1st meal) determined by available CHO and the weight or amount of bagel consumed: treatment A, without RS (50 g of available CHO); treatment B, with RS (same total CHO as in A); treatment C, with RS (same available CHO as in A); and treatment D, with the same RS as in B and available CHO as in A and C. A standard 2nd meal was ingested 3 h later. Following the first meal, B elicited a lower glucose incremental area under the curve (iAUC) than C (P < 0.05), D (P < 0.05), and A (trend; P = 0.07), lower insulin iAUC than A (P < 0.05) and C (P < 0.05), and lower glucose-dependent insulinotropic polypeptide (GIP) iAUC than A (P < 0.05). There was a positive correlation (P < 0.05) between GIP and insulin iAUCs after the 2nd meal, and C had a 3 times greater slope than the other treatments (r = 0.91, P < 0.001), yet lacked a significant concomitant improvement in glucose disposal. These results show that for the 1st meal, RS was effective when it replaced a portion of the available CHO, while ingesting more RS influenced the GIP–insulin axis following the 2nd meal.

Evaluation and treatment of hypertriglyceridemia: an Endocrine Society clinical practice guideline

OBJECTIVE

The aim was to develop clinical practice guidelines on hypertriglyceridemia.

PARTICIPANTS

The Task Force included a chair selected by The Endocrine Society Clinical Guidelines Subcommittee (CGS), five additional experts in the field, and a methodologist. The authors received no corporate funding or remuneration.

CONSENSUS PROCESS

Consensus was guided by systematic reviews of evidence, e-mail discussion, conference calls, and one in-person meeting. The guidelines were reviewed and approved sequentially by The Endocrine Society's CGS and Clinical Affairs Core Committee, members responding to a web posting, and The Endocrine Society Council. At each stage, the Task Force incorporated changes in response to written comments.

CONCLUSIONS

The Task Force recommends that the diagnosis of hypertriglyceridemia be based on fasting levels, that mild and moderate hypertriglyceridemia (triglycerides of 150-999 mg/dl) be diagnosed to aid in the evaluation of cardiovascular risk, and that severe and very severe hypertriglyceridemia (triglycerides of > 1000 mg/dl) be considered a risk for pancreatitis. The Task Force also recommends that patients with hypertriglyceridemia be evaluated for secondary causes of hyperlipidemia and that subjects with primary hypertriglyceridemia be evaluated for family history of dyslipidemia and cardiovascular disease. The Task Force recommends that the treatment goal in patients with moderate hypertriglyceridemia be a non-high-density lipoprotein cholesterol level in agreement with National Cholesterol Education Program Adult Treatment Panel guidelines. The initial treatment should be lifestyle therapy; a combination of diet modification and drug therapy may also be considered. In patients with severe or very severe hypertriglyceridemia, a fibrate should be used as a first-line agent.

Lipid transfer to HDL is higher in marathon runners than in sedentary subjects, but is acutely inhibited during the run

Although exercise increases HDL-cholesterol, exercise-induced changes in HDL metabolism have been little explored. Lipid transfer to HDL is essential for HDL's role in reverse cholesterol transport. We investigated the effects of acute exhaustive exercise on lipid transfer to HDL. We compared plasma lipid, apolipoprotein and cytokine levels and in vitro transfer of four lipids from a radioactively labeled lipid donor nanoemulsion to HDL in sedentary individuals (n = 28) and in marathon runners (n = 14) at baseline, immediately after and 72 h after a marathon. While HDL-cholesterol concentrations and apo A1 levels were higher in marathon runners, LDL-cholesterol, apo B and triacylglycerol levels were similar in both groups. Transfers of non-esterified cholesterol [6.8 (5.7-7.2) vs. 5.2 (4.5-6), p = 0.001], phospholipids [21.7 (20.4-22.2) vs. 8.2 (7.7-8.9), p = 0.0001] and triacylglycerol [3.7 (3.1-4) vs. 1.3 (0.8-1.7), p = 0.0001] were higher in marathon runners, but esterified-cholesterol transfer was similar. Immediately after the marathon, LDL- and HDL-cholesterol concentrations and apo A1 levels were unchanged, but apo B and triacylglycerol levels increased. Lipid transfer of non-esterified cholesterol [6.8 (5.7-7.2) vs. 5.8 (4.9-6.6), p = 0.0001], phospholipids [21.7 (20.4-22.2) vs. 19.1 (18.6-19.3), p = 0.0001], esterified-cholesterol [3.2 (2.2-3.8) vs. 2.3 (2-2.9), p = 0.02] and triacylglycerol [3.7 (3.1-4) vs. 2.6 (2.1-2.8), p = 0.0001] to HDL were all reduced immediately after the marathon but returned to baseline 72 h later. Running a marathon increased IL-6 and TNF-α levels, but after 72 h these values returned to baseline. Lipid transfer, except esterified-cholesterol transfer, was higher in marathon runners than in sedentary individuals, but the marathon itself acutely inhibited lipid transfer. In light of these novel observations, further study is required to clarify how these metabolic changes can influence HDL composition and anti-atherogenic function.

Fructose: a highly lipogenic nutrient implicated in insulin resistance, hepatic steatosis, and the metabolic syndrome

As dietary exposure to fructose has increased over the past 40 years, there is growing concern that high fructose consumption in humans may be in part responsible for the rising incidence of obesity worldwide. Obesity is associated with a host of metabolic challenges, collectively termed the metabolic syndrome. Fructose is a highly lipogenic sugar that has profound metabolic effects in the liver and has been associated with many of the components of the metabolic syndrome (insulin resistance, elevated waist circumference, dyslipidemia, and hypertension). Recent evidence has also uncovered effects of fructose in other tissues, including adipose tissue, the brain, and the gastrointestinal system, that may provide new insight into the metabolic consequences of high-fructose diets. Fructose feeding has now been shown to alter gene expression patterns (such as peroxisome proliferator-activated receptor-γ coactivator-1α/β in the liver), alter satiety factors in the brain, increase inflammation, reactive oxygen species, and portal endotoxin concentrations via Toll-like receptors, and induce leptin resistance. This review highlights recent findings in fructose feeding studies in both human and animal models with a focus on the molecular and biochemical mechanisms that underlie the development of insulin resistance, hepatic steatosis, and the metabolic syndrome.

New oral fat tolerance tests feature tailoring of the polyunsaturated/saturated fatty acid ratio to elicit a specific postprandial response

The impact of dietary fat on postprandial metabolic biomarkers for obesity-related chronic diseases, such as type-2 diabetes and cardiovascular disease, has received significant recent attention. However, there is no standard method to evaluate the postprandial response to dietary fat alone. Our goals were to develop a novel oral fat tolerance test (OFTT) consisting solely of emulsified lipids tailored for specific fatty acid compositions and to evaluate the functionality of specific ratios of polyunsaturated/saturated fatty acid (P/S) loading on postprandial triacylglyceride (TAG) concentrations. Two OFTTs of emulsified lipids were prepared with specific P/S ratios of 0.2 and 2.0. Physical characteristics of the fat blends, including TAG composition, melting point, and emulsion droplet size were quantified. Healthy, older (age > 45 y) men (n = 8) underwent an 8 h postprandial study wherein they received the OFTT treatment (either the P/S ratio of 0.2 or 2.0), with a total lipid load of 1 g/kg subject body mass. All subjects received both treatments separated by at least 1 week. Both the P/S 0.2 and 2.0 OFTT significantly elevated (p < 0.05) blood TAG and free fatty acid concentrations for 8 h without increasing blood glucose or serum insulin concentrations. The predominant fatty acids contained in the P/S 0.2 (palmitic acid, 16:0) and 2.0 (linoleic acid, 18:2(n–6)) OFTT blends were significantly elevated in the blood (p < 0.05) during their respective postprandial periods. We concluded that blood TAGs are elevated in a specific pattern through the administration of novel OFTTs with specific P/S blends without eliciting an insulin or glucose response.

Effect of exercise duration on postprandial hypertriglyceridemia in men with metabolic syndrome

We examined the effect of exercise on postprandial hypertriglyceridemia (PHTG) and insulin resistance in individuals with metabolic syndrome. Subjects were 10 hypertriglyceridemic men with insulin resistance [age = 35.0 ± 1.8 yr, body weight = 90.7 ± 3.3 kg, fasting triglyceride (TG) = 2.6 ± 0.4 mmol/l, peak oxygen consumption (V̇o2peak) = 36.0 ± 1.3 ml−1·kg−1·min−1, and homeostatic model assessment of insulin resistance (HOMA-IR)= 3.1 ± 0.3]. Each participant performed a control trial (Ctr; no exercise) and three exercise trials at 60% of their V̇o2peakfor 30 min (30 min-Ex), 45 min (45 min-Ex) and 60 min (60 min-Ex). All subjects had a fat meal in each trial. In the exercise trials, the subject jogged on a treadmill for a designated duration of 12 h before ingestion of a fat meal. Blood samples were taken at 0 h (before the meal) and at 2, 4, 6, and 8 h after the meal. The plasma TG, area score under TG concentration curve over an 8-h period (TG AUC) after the meal, and HOMA-IR were analyzed. The TG AUC scores in both the 45 min-Ex and 60 min-Ex were 31 and 33% lower, respectively, than Ctr ( P < 0.02). There were no significant differences in TG AUC scores between the 30 min-Ex and the Ctr ( P > 0.05). There were no trial differences in the fasting plasma glucose concentration ( P > 0.05). HOMA-IR values in the 30 min-Ex, 45 min-Ex, and 60 min-Ex trials were lower than the Ctr ( P < 0.03), but no significant differences were found in HOMA-IR among the exercise trials. The results suggest that for physically inactive individuals with metabolic syndrome, exercising at moderate intensity for 45 min effectively attenuates PHTG while exercise for 30 min is sufficient to improve insulin action.

Regulation of postprandial lipemia: an update on current trends

People spend a large percentage of their waking hours in the postprandial state. Postprandial lipemia is associated with disruptions in lipoprotein metabolism and inflammatory factors, cardiovascular disease, MetS, and diabetes. Commonly, the dietary sources of fat exceed the actual needs and the tissues are faced with the excess, with accumulation of chylomicrons and remnant particles. This review will summarize recent findings in postprandial lipemia research with a focus on human studies. The effects of dietary factors and other meal components on postprandial lipemia leads to the following question: do we need a standardized oral lipid tolerance test (OLTT)? An overview of recent findings on FABP2, MTP, LPL, apoAV, and ASP and the effects of body habitus (sex influence and body size), as well as exercise and weight loss, on postprandial lipemia will be summarized.