High postprandial triglyceridemia in patients with type 2 diabetes and microalbuminuria

The postprandial actions of GLP-1 receptor agonists: The missing link for cardiovascular and kidney protection in type 2 diabetes

Recent clinical trials in people with type 2 diabetes have demonstrated beneficial actions on heart and kidney outcomes following treatment with GLP-1RAs. In part, these actions are consistent with improved glucose control and significant weight loss. But GLP-1RAs may also have additive benefits by improving postprandial dysmetabolism. In diabetes, dysregulated postprandial nutrient excursions trigger inflammation, oxidative stress, endothelial dysfunction, thrombogenicity, and endotoxemia; alter hormone levels; and modulate cardiac output and regional blood and lymphatic flow. In this perspective, we explore the actions of GLP-1RAs on the postprandial state and their potential role in end-organ benefits observed in recent trials.

The Association of Postprandial Triglyceride Variability with Renal Dysfunction and Microalbuminuria in Patients with Type 2 Diabetic Mellitus: A Retrospective and Observational Study

OBJECTIVE

We examined whether or not day-to-day variations in lipid profiles, especially triglyceride (TG) variability, were associated with the exacerbation of diabetic kidney disease.

METHODS

We conducted a retrospective and observational study. First, 527 patients with type 2 diabetes mellitus (DM) who had had their estimated glomerular filtration rate (eGFR) checked every 6 months since 2012 for over 5 years were registered. Variability in postprandial TG was determined using the standard deviation (SD), SD adjusted (Adj-SD) for the number of measurements, and maximum minus minimum difference (MMD) during the first three years of follow-up. The endpoint was a ≥40% decline from baseline in the eGFR, initiation of dialysis or death. Next, 181 patients who had no micro- or macroalbuminuria in February 2013 were selected from among the 527 patients for an analysis. The endpoint was the incidence of microalbuminuria, initiation of dialysis, or death.

RESULTS

Among the 527 participants, 110 reached a ≥40% decline from baseline in the eGFR or death. The renal survival was lower in the higher-SD, higher-Adj-SD, and higher-MMD groups than in the lower-SD, lower-Adj-SD, and lower-MMD groups, respectively (log-rank test p = 0.0073, 0.0059, and 0.0195, respectively). A lower SD, lower Adj-SD, and lower MMD were significantly associated with the renal survival in the adjusted model (hazard ratio, 1.62, 1.66, 1.59; 95% confidence intervals, 1.05-2.53, 1.08-2.58, 1.04-2.47, respectively). Next, among 181 participants, 108 developed microalbuminuria or death. The nonincidence of microalbuminuria was lower in the higher-SD, higher-Adj-SD, and higher-MMD groups than in the lower-SD, lower-Adj-SD, and lower-MMD groups, respectively (log-rank test p = 0.0241, 0.0352, and 0.0474, respectively).

CONCLUSIONS

Postprandial TG variability is a novel risk factor for eGFR decline and the incidence of microalbuminuria in patients with type 2 DM.

Postprandial Hypertriglyceridaemia Revisited in the Era of Non-Fasting Lipid Profile Testing: A 2019 Expert Panel Statement, Main Text

Residual vascular risk exists despite the aggressive lowering of Low-Density Lipoprotein Cholesterol (LDL-C). A contributor to this residual risk may be elevated fasting, or non-fasting, levels of Triglyceride (TG)-rich lipoproteins. Therefore, there is a need to establish whethe a standardised Oral Fat Tolerance Test (OFTT) can improve atherosclerotic Cardiovascular (CV) Disease (ASCVD) risk prediction in addition to a fasting or non-fasting lipid profile. An expert panel considered the role of postprandial hypertriglyceridaemia (as represented by an OFTT) in predicting ASCVD. The panel updated its 2011 statement by considering new studies and various patient categories. The recommendations are based on expert opinion since no strict endpoint trials have been performed. Individuals with fasting TG concentration <1 mmol/L (89 mg/dL) commonly do not have an abnormal response to an OFTT. In contrast, those with fasting TG concentration ≥2 mmol/L (175 mg/dL) or nonfasting ≥2.3 mmol/L (200 mg/dL) will usually have an abnormal response. We recommend considering postprandial hypertriglyceridaemia testing when fasting TG concentrations and non-fasting TG concentrations are 1-2 mmol/L (89-175 mg/dL) and 1.3-2.3 mmol/L (115-200 mg/dL), respectively as an additional investigation for metabolic risk prediction along with other risk factors (obesity, current tobacco abuse, metabolic syndrome, hypertension, and diabetes mellitus). The panel proposes that an abnormal TG response to an OFTT (consisting of 75 g fat, 25 g carbohydrate and 10 g proteins) is >2.5 mmol/L (220 mg/dL). Postprandial hypertriglyceridaemia is an emerging factor that may contribute to residual CV risk. This possibility requires further research. A standardised OFTT will allow comparisons between investigational studies. We acknowledge that the OFTT will be mainly used for research to further clarify the role of TG in relation to CV risk. For routine practice, there is a considerable support for the use of a single non-fasting sample.

Roux-en-Y Gastric Bypass Is More Effective than Sleeve Gastrectomy in Improving Postprandial Glycaemia and Lipaemia in Non-diabetic Morbidly Obese Patients: a Short-term Follow-up Analysis

PURPOSE

We aimed to compare the effects of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on postprandial glucose and lipid metabolism in addition to weight loss and fasting metabolic profile, in non-diabetic patients undergoing bariatric surgery.

METHODS

Seventy-one patients were consecutively recruited and studied preoperatively, 3 and 6 months after surgery. Of these, 28 underwent RYGB (7 males, age 38 ± 9 years, BMI 46.9 ± 5.0 kg/m²), and 43 SG (9 males, age 38 ± 9 years, BMI 50.2 ± 7.0 kg/m²). A semi-liquid mixed meal was consumed, and blood samples were taken before, and every 30 min after meal ingestion up to 180 min postprandially, for measurement of glucose, insulin, and lipids. The overall postprandial response was assessed as area under the concentration-time curve (AUC).

RESULTS

Baseline metabolic parameters were similar between RYGB and SG. Both groups experienced comparable weight loss, and a similar improvement in fasting glucose, insulin, and insulin resistance. Total and LDL cholesterol levels were lower at 6 months after RYGB compared to SG, while there was no difference in HDL cholesterol or triglycerides. Glucose AUC was lower after RYGB compared to SG at both 3 (p = 0.008) and 6 months (p = 0.016), without any difference in postprandial insulin response. Triglyceride AUC was also lower in RYGB vs. SG at 3 and 6 months (p ≤ 0.001).

CONCLUSIONS

RYGB is superior to SG in improving postprandial glycaemia and lipaemia and cholesterol profile 6 months postoperatively in non-diabetic, severely obese patients. These findings imply procedure-specific effects, such as the malabsorptive nature of RYGB, and less likely a different incretin postoperative response.

Dyslipidaemia in nephrotic syndrome: mechanisms and treatment

Nephrotic syndrome is a highly prevalent disease that is associated with high morbidity despite notable advances in its treatment. Many of the complications of nephrotic syndrome, including the increased risk of atherosclerosis and thromboembolism, can be linked to dysregulated lipid metabolism and dyslipidaemia. These abnormalities include elevated plasma levels of cholesterol, triglycerides and the apolipoprotein B-containing lipoproteins VLDL and IDL; decreased lipoprotein lipase activity in the endothelium, muscle and adipose tissues; decreased hepatic lipase activity; and increased levels of the enzyme PCSK9. In addition, there is an increase in the plasma levels of immature HDL particles and reduced cholesterol efflux. Studies from the past few years have markedly improved our understanding of the molecular pathogenesis of nephrotic syndrome-associated dyslipidaemia, and also heightened our awareness of the associated exacerbated risks of cardiovascular complications, progressive kidney disease and thromboembolism. Despite the absence of clear guidelines regarding treatment, various strategies are being increasingly utilized, including statins, bile acid sequestrants, fibrates, nicotinic acid and ezetimibe, as well as lipid apheresis, which seem to also induce partial or complete clinical remission of nephrotic syndrome in a substantial percentage of patients. Future potential treatments will likely also include inhibition of PCSK9 using recently-developed anti-PCSK9 monoclonal antibodies and small inhibitory RNAs, as well as targeting newly identified molecular regulators of lipid metabolism that are dysregulated in nephrotic syndrome.

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 a liquid high-fat meal on postprandial lipid metabolism in type 2 diabetic patients with abdominal obesity

Background

Postprandial lipemia and lipoprotein lipase (LPL) activity play crucial roles in the pathogenesis of accelerated atherosclerosis. This study aimed to evaluate the postprandial lipid metabolism after the ingestion of a liquid high-fat meal in type 2 diabetic patients with abdominal obesity, and determine if the PvuII polymorphisms of LPL influence their postprandial lipid responses.

Methods

Serum glucose, insulin, triglycerides (TG), total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C) were measured in fasting and postprandial state at 0.5, 1, 2, 4, 6 and 8 h after a liquid high-fat meal in 51 type 2 diabetic patients with abdominal obesity, 31 type 2 diabetic patients without abdominal obesity and 39 controls. Their PvuII polymorphisms of LPL were tested in fasting.

Results

Type 2 diabetic patients with abdominal obesity had significantly higher postprandial areas under the curve (AUC) of glucose [least square mean difference (LSMD) = 30.763, 95% confidence interval (CI) = 23.071–38.455, F = 37.346, P < 0.05] and TC (LSMD = 3.995, 95% CI = 1.043–6.947, F = 3.681, P < 0.05) than controls. Postprandial AUCs for insulin, homeostasis model assessment-insulin resistance (HOMA-IR) and TG were higher (LSMD = 86.987, 95% CI = 37.421–136.553, F = 16.739, P < 0.05; LSMD = 37.456, 95% CI = 16.312–58.600, F = 27.012, P < 0.05; LSMD = 4.684, 95% CI = 2.662–6.705, F = 26.158, P < 0.05), whereas HDL-C AUC was lower (LSMD = −1.652, 95% CI = −2.685 – -0.620, F = 8.190, P < 0.05) in type 2 diabetic subjects with abdominal obesity than those without abdominal obesity. In type 2 diabetic patients with abdominal obesity, postprandial TG AUC was lower in P−/− than in P+/− (LSMD = −4.393, 95% CI = −9.278 – -0.491, F = 4.476, P < 0.05) and P+/+ (LSMD = −7.180, 95% CI = −12.319 – -2.014, F = 4.476, P < 0.05) phenotypes. Postprandial AUCs for glucose, insulin, HOMA-IR, TC and HDL-C were not different according to PvuII phenotypes.

Conclusions

Abdominal obesity exacerbates the postprandial lipid responses in type 2 diabetic patients, which partly explains the excess atherogenic risk in these patients. In addition, the presence of P+ allele could contribute to a greater postprandial TG increase in type 2 diabetic patients with abdominal obesity.

Trial registration

ChiCTR-IOR-16008435. Registered 8 May 2016.

Postmeal triglyceridemia and variability of HbA1c and postmeal glycemia were predictors of annual decline in estimated glomerular filtration rate in type 2 diabetic patients with different stages of nephropathy

BACKGROUND

This study examined associations of annual glycemic variability and postprandial dysmetabolism with annual decline in estimated glomerular filtration rate (eGFR) in type 2 diabetic patients with different stages of nephropathy.

METHODS

Intrapersonal mean and coefficient of variation (CV) of HbA1c, fasting and postmeal concentrations of plasma glucose (FPG and PMPG, respectively) and serum triglycerides (FTG and PMTG, respectively) during the first 12 months after enrollment were calculated in a cohort of 168 type 2 diabetic patients: 53 with optimal albumin/creatinine ratio (ACR < 10 mg/g), 62 with high normal ACR (10-29 mg/g) and 53 with elevated ACR (≧30 mg/g). Annual changes in eGFR were computed using 52 (median) creatinine measurements obtained over a median follow-up of 6.0 years. Multivariate linear regressions assessed the independent correlates of changes in eGFR.

RESULTS

Kidney function declined faster in patients with high normal and elevated ACR (-1.47 and -2.01 ml/min/1.73 m2/year, respectively) compared to patients with optimal ACR (0.08 ml/min/1.73 m2/year, p < 0.05). In patients with high normal ACR, age (standardized β、-0.30、p = 0.01), CV-HbA1c (standardized β、-0.66、p < 0.001) and CV-PMPG (standardized β、-0.27、p = 0.01) was associated with annual eGFR decline independently of mean HbA1c and PMPG, sex, BMI, waist circumference, diabetes duration and therapy, means and CVs of FPG and systolic blood pressure, baseline eGFR, log ACR and uses of anti-hypertensive medications (R2 = 0.47). In patients with elevated ACR, PMTG (standardized β、-0.408, p = 0.007) was associated with annual eGFR decline (R2 = 0.15).

CONCLUSIONS

Consistency of glycemic control and management of postprandial glycemia and lipidemia are important to preserve kidney function in type 2 diabetic patients.

Hepatic insulin resistance both in prediabetic and diabetic patients determines postprandial lipoprotein metabolism: from the CORDIOPREV study

Background/aims

Previous evidences have shown the presence of a prolonged and exaggerated postprandial response in type 2 diabetes mellitus (T2DM) and its relation with an increase of cardiovascular risk. However, the response in prediabetes population has not been established. The objective was to analyze the degree of postprandial lipemia response in the CORDIOPREV clinical trial (NCT00924937) according to the diabetic status.

Methods

1002 patients were submitted to an oral fat load test meal (OFTT) with 0.7 g fat/kg body weight [12 % saturated fatty acids (SFA), 10 % polyunsaturated fatty acids (PUFA), 43 % monounsaturated fatty acids (MUFA), 10 % protein and 25 % carbohydrates]. Serial blood test analyzing lipid fractions were drawn at 0, 1, 2, 3 and 4 h during postprandial state. Postprandial triglycerides (TG) concentration at any point >2.5 mmol/L (220 mg/dL) has been established as undesirable response. We explored the dynamic response in 57 non-diabetic, 364 prediabetic and 581 type 2 diabetic patients. Additionally, the postprandial response was evaluated according to basal insulin resistance subgroups in patients non-diabetic and diabetic without pharmacological treatment (N = 642).

Results

Prevalence of undesirable postprandial TG was 35 % in non-diabetic, 48 % in prediabetic and 59 % in diabetic subgroup, respectively (p < 0.001). Interestingly, prediabetic patients displayed higher plasma TG and large triacylglycerol-rich lipoproteins (TRLs-TG) postprandial response compared with those non-diabetic patients (p < 0.001 and p = 0.003 respectively). Moreover, the area under the curve (AUC) of TG and AUC of TRLs-TG was greater in the prediabetic group compared with non-diabetic patients (p < 0.001 and p < 0.005 respectively). Patients with liver insulin resistance (liver-IR) showed higher postprandial response of TG compared with those patients with muscle-IR or without any insulin-resistance respectively (p < 0.001).

Conclusions

Our findings demonstrate that prediabetic patients show a lower phenotypic flexibility after external aggression, such as OFTT compared with nondiabetic patients. The postprandial response increases progressively according to non-diabetic, prediabetic and type 2 diabetic state and it is higher in patients with liver insulin-resistance. To identify this subgroup of patients is important to treat more intensively in order to avoid future cardiometabolic complications.

Association of Postbreakfast Triglyceride and Visit-to-Visit Annual Variation of Fasting Plasma Glucose with Progression of Diabetic Nephropathy in Patients with Type 2 Diabetes

Urinary albumin/creatinine ratio (ACR) was measured at baseline and after a median follow-up of 6.0 years in 161 patients with type 2 diabetes. Intrapersonal means and SD of HbA1c, systolic BP, fasting, and postmeal plasma glucose (FPG and PMPG, resp.) and serum triglycerides (FTG and PMTG, resp.) were calculated in each patient during the first 12 months after enrollment. Associations of these variables with nephropathy progression (15 patients with progression of albuminuric stages and 5 with ACR doubling within the microalbuminuric range) were determined by multivariate logistic regression analysis providing odds ratio with 95% confidential interval. Patients with nephropathy progression, compared with those without nephropathy progression, had higher HbA1c (p < 0.01). They also had higher means and SD of FPG (both p < 0.05), FTG (both p < 0.05), and PMTG (p = 0.001). Multivariate logistic regression analysis demonstrated that SD-FPG (1.036, 1.001-1.073, p = 0.04) and PMTG (1.013, 1.008-1.040, p = 0.001) were significant predictors of progression of nephropathy even after adjustment for mean FPG and SD-FTG, age, sex, BMI, waist circumference, diabetes duration and therapy, means and SDs of HbA1c, PPG, FTG and systolic BP, baseline ACR, smoking status, and uses of antihypertensive and lipid-lowering medications. Consistency of glycemic control and management of postmeal TG may be important to prevent nephropathy progression in type 2 diabetic patients.

Protein biomarkers for the prediction of cardiovascular disease in type 2 diabetes

AIMS/HYPOTHESIS

We selected the most informative protein biomarkers for the prediction of incident cardiovascular disease (CVD) in people with type 2 diabetes.

METHODS

In this nested case-control study we measured 42 candidate CVD biomarkers in 1,123 incident CVD cases and 1,187 controls with type 2 diabetes selected from five European centres. Combinations of biomarkers were selected using cross-validated logistic regression models. Model prediction was assessed using the area under the receiver operating characteristic curve (AUROC).

RESULTS

Sixteen biomarkers showed univariate associations with incident CVD. The most predictive subset selected by forward selection methods contained six biomarkers: N-terminal pro-B-type natriuretic peptide (OR 1.69 per 1 SD, 95% CI 1.47, 1.95), high-sensitivity troponin T (OR 1.29, 95% CI 1.11, 1.51), IL-6 (OR 1.13, 95% CI 1.02, 1.25), IL-15 (OR 1.15, 95% CI 1.01, 1.31), apolipoprotein C-III (OR 0.79, 95% CI 0.70, 0.88) and soluble receptor for AGE (OR 0.84, 95% CI 0.76, 0.94). The prediction of CVD beyond clinical covariates improved from an AUROC of 0.66 to 0.72 (AUROC for Framingham Risk Score covariates 0.59). In addition to the biomarkers, the most important clinical covariates for improving prediction beyond the Framingham covariates were estimated GFR, insulin therapy and HbA1c.

CONCLUSIONS/INTERPRETATION

We identified six protein biomarkers that in combination with clinical covariates improved the prediction of our model beyond the Framingham Score covariates. Biomarkers can contribute to improved prediction of CVD in diabetes but clinical data including measures of renal function and diabetes-specific factors not included in the Framingham Risk Score are also needed.

A comparative study on the fasting and the postprandial dyslipidaemia in type 2 diabetes mellitus

BACKGROUND AND OBJECTIVES

Type 2 Diabetes Mellitus (Type 2 DM), which is characterized by a relative insulin deficiency or insulin resistance is associated with a cluster of metabolic abnormalities, which includes glucose intolerance, hypertension, a unique dyslipidaemia, a procoagulant state, and an increase in macrovascular diseases. The present study was conducted to assess the significance of postprandial dyslipidaemia with respect to fasting dyslipidaemia, in the pathogenesis of atherosclerotic changes and possible cardiovascular diseases (CVD) and complications. Methods and Statistical Analysis: Fifty diagnosed cases of type 2 DM which were in the age group of 35-65 years, which had a duration of diabetes of more than five years, were included in the study and 50 age and sex matched healthy subjects were taken as the controls. In both the study groups, we measured the serum levels of fasting as well as the postprandial lipid profile, which was comprised of the total Cholesterol (TC), triglycerides (TGs), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and the waist-hip ratio (WHI) as the cardiovascular risk factors. The statistical analysis was done by using the Students unpaired 't'-test.

RESULTS

The results of this study showed significantly increased levels of serum total cholesterol, TGs, LDL-C and VLDL-C in the postprandial state as compared to those in the fasting state (p<0.001) and as compared to those in the fasting and the postprandial states of the controls (p<0.001). The serum HDL-C level was significantly lower in the postprandial state as compared to that in the fasting state (p<0.001). Also, the postprandial and the fasting HDL-C levels were significantly lower as compared to the levels in their respective control groups (p<0.001).

CONCLUSION

The findings of the present study indicated that the lipid profile, as a cardiovascular risk factor, was significantly elevated in the postprandial state as compared to that in the fasting state and that it was significantly elevated in the postprandial and the fasting states in the Type 2 DM patients as compared to the levels in their respective control groups. This signified a routine estimation of the postprandial lipid profile, rather than the fasting lipid parameters, in the cardiovascular risk assessment in Type 2 DM.

Fasting APO B48 levels are associated with microalbuminuria in patients with type 2 diabetes

In view of the high incidence of macrovascular diseases in patients with type 2 diabetes mellitus and microalbuminuria, the study evaluates the association of microalbuminuria with fasting plasma Apo B48 levels, a marker of the residual presence of intestinally derived TRLs lipoproteins, thought to be highly atherogenic. We studied 50 patients with type 2 diabetes aged 35-75 years. Exclusion criteria were overt macrovascular disease, overt nephropathy (Glomerular filtration rate (GFR) <45 ml/min/1.73 m(2)), or use of hypolipidemic agents. Anthropometry, fasting plasma lipids, plasma creatinine, and HbA1c were measured. Urinary albumin excretion was measured on a morning urine sample with the ELISA and expressed as albumin/creatinine ratio. GFR was estimated using the MDRD formula. The plasma fasting Apo B48 was measured by ELISA. Age, gender distribution, fasting plasma lipids, HbA1c, smoking status, plasma creatinine, estimate GFR, and the proportion of patients treated with insulin or antihypertensive drugs were similar for patients with or without microalbuminuria. People with microalbuminuria had longer diabetes duration (borderline significance) and significantly higher Apo B48 (1.765 ± 1.379 μg/ml vs. 1.022 ± 0.692 μg/ml, p = 0.01) than those without microalbuminuria. Multivariate logistic regression analysis confirmed that fasting Apo B48 levels were significantly associated with microalbuminuria independent of major confounders measured in the study. In patients with type 2 diabetes, microalbuminuria is associated with elevated Apo B48 levels, independent of major confounders; this may partly explain the excess cardiovascular risk of these patients.

Effects of a meal rich in 1,3-diacylglycerol on postprandial cardiovascular risk factors and the glucose-dependent insulinotropic polypeptide in subjects with high fasting triacylglycerol concentrations

It was previously reported that compared to triacylglycerol (TAG) oil, diacylglycerol (DAG) oil improves postprandial lipid response. However, the effects of DAG oil on postprandial hyperglycemia and incretin response have not yet been determined. In this study, the effects of DAG oil on both postprandial hyperlipidemia and hyperglycemia and the response to the glucose-dependent insulinotropic polypeptide (GIP) were studied. This randomized, double-blind, crossover study analyzed data for 41 individuals with high fasting triacylglycerol concentrations. The subjects ingested test meals (30.3 g of protein, 18.6 g of fat, and 50.1 g of carbohydrate) containing 10 g of DAG oil (DAG meal) or TAG oil (TAG meal) after fasting for at least 12 h. Blood samples were collected prior to and 0.5, 2, 3, 4, and 6 h after ingestion of the test meal. Postprandial TAG concentrations were significantly lower after the DAG meal compared with the TAG meal. Postprandial TAG, insulin, and GIP concentrations were significantly lower after the DAG meal compared with the TAG meal in 26 subjects with fasting serum TAG levels between 1.36 and 2.83 mmol/L. DAG-oil-based meals, as a replacement for TAG oil, may provide cardiovascular benefits in high-risk individuals by limiting lipid and insulin excursions.

Effects of meals rich in either monounsaturated or saturated fat on lipid concentrations and on insulin secretion and action in subjects with high fasting triglyceride concentrations

BACKGROUND

The nature of dietary fats and fasting concentrations of triglycerides affect postprandial hypertriglyceridemia and glucose homeostasis.

OBJECTIVES

The objectives were to examine the effects of meals enriched in monounsaturated fatty acids (MUFAs) or saturated fatty acids (SFAs) on postprandial lipid, glucose, and insulin concentrations and to examine the extent of β cell function and insulin sensitivity in subjects with high fasting triglyceride concentrations.

DESIGN

Fourteen men with fasting hypertriglyceridemia and normal glucose tolerance were given meals (≈10 kcal/kg body weight) containing MUFAs, SFAs, or no fat. Blood samples were collected at baseline and hourly over 8 h for analysis.

RESULTS

The high-fat meals significantly increased postprandial concentrations of triglycerides, nonesterified fatty acids, and insulin and postprandial indexes of β cell function. However, postprandial indexes of insulin sensitivity decreased significantly. These effects were significantly attenuated with MUFAs relative to SFAs.

CONCLUSIONS

MUFAs postprandially buffered β cell hyperactivity and insulin intolerance relative to SFAs in subjects with high fasting triglyceride concentrations. These data suggest that, in contrast with SFAs, MUFA-based strategies may provide cardiovascular benefits to persons at risk by limiting lipid and insulin excursions and may contribute to optimal glycemic control after meal challenges.

Postprandial lipoproteins and cardiovascular disease risk in diabetes mellitus

Diabetes mellitus is associated with increased risk for atherosclerotic cardiovascular disease (CVD). Recent prospective studies in healthy individuals suggest that the postprandial triglyceride (TG) level is a better independent predictor for assessing future CVD events than fasting TG levels. In contrast, results have been more controversial among diabetic patients, as some studies report a positive association between postprandial TG and CVD. This raises the issue of to what extent postprandial TG levels may be of predictive value in the diabetic population. One possibility impacting on the predictive power of postprandial TG in identifying CVD risk may be the presence of other risk factors, including alterations in lipid and lipoprotein metabolism, which could make it more difficult to identify the impact of postprandial lipemia on cardiovascular risk. The findings provide a challenge to develop a better approach to assess the impact of postprandial lipemia on CVD risk under diabetic conditions.

Microalbuminuria and metabolic risk factors in patients with type 2 diabetes in primary care setting in Thailand

OBJECTIVE

To determine the prevalence of microalbuminuria and associated risk factors in patients with type 2 diabetes in primary care.

METHODS

Clinical information of diabetic patients in 70 primary care units in Thailand was collected in a cross-sectional survey. Multinomial logistic regression model was used to examine several clinical risk factors with microalbuminuria and macroalbuminuria.

RESULTS

A total of 4162 patients were included. The prevalence of microalbuminuria was 39.12% and macroalbumninuria was 7.83%. The proportion of patients with HbA1c<7% was 37.9%. Independent risk factors for microalbuminuria and macroalbuminuria included HbA1c (adjusted OR 1.54, 95%CI 1.30-1.83 and 2.06, 95%CI 1.49-2.84 per unit increase in HbA1c, respectively), triglyceride >/=1.7mmol/L (1.31, 1.11-1.56 and 1.44, 1.06-1.98), hypertension (1.31, 1.10-1.54 and 1.64, 1.23-2.20), and duration of diabetes >/=5 years (1.31, 1.11-1.55 and 2.39, 1.74-3.28). Metabolic syndrome was associated with macroalbuminuria (OR 1.36, 95%CI 1.01-1.84).

CONCLUSION

The high prevalence of microabuminuria and suboptimal glycemic control for the diabetic patients were found to highlight the need to improve in control of glycemia and metabolic risk factors.

Significant increase of apolipoprotein B48 levels by a standard test meal in type 2 diabetic patients with nephropathy

AIM

We investigated postprandial changes of apolipoprotein (apo) B48 in type 2 diabetics at different stages of diabetic nephropathy in order to explore non-traditional lipid abnormalities in diabetic nephropathy.

METHODS

Twenty-two healthy controls and 56 type 2 diabetics with normoalbuminuria (NA), microalbuminuria (MA), and overt albuminuria (OA) were enrolled. Blood samples were taken at 0, 1, 2, 4, 6 h after the ingestion of Test meal A (460 Kcal, 18 g fat). The maximal increase of triglyceride (TG) was 40% above baseline in controls and 17% above baseline in diabetics. The incremental area under the curve (iAUC) of TG, however, was comparable among controls and diabetics with NA, MA, and OA. The maximal increase of apoB48 was 92% above baseline in controls and 56-88% above baseline in diabetics. Apo B48-iAUC was significantly higher in diabetics than in controls, and diabetics with OA exhibited the highest apoB48-iAUC among the diabetic subgroups. Small dense low-density lipoprotein-cholesterol (LDL-C) was elevated in diabetic nephropathy, and apoB48-iAUC was positively associated with the level of sd-LDL-C.

CONCLUSIONS

ApoB48 is a sensitive marker for postprandial lipemia, a condition which is significantly increased in diabetic nephropathy and associated with an increase of potent atherogenic sd- LDL particles.

Distinctive postprandial modulation of beta cell function and insulin sensitivity by dietary fats: monounsaturated compared with saturated fatty acids

BACKGROUND

Exaggerated and prolonged postprandial triglyceride concentrations are associated with numerous conditions related to insulin resistance, including obesity, type 2 diabetes, and the metabolic syndrome. Although dietary fats profoundly affect postprandial hypertriglyceridemia, limited data exist regarding their effects on postprandial glucose homeostasis.

OBJECTIVE

We sought to determine whether postprandial glucose homeostasis is modulated distinctly by high-fat meals enriched in saturated fatty acids (SFAs) or monounsaturated fatty acids (MUFAs).

DESIGN

Normotriglyceridemic subjects with normal fasting glucose and normal glucose tolerance were studied. Blood samples were collected over the 8 h after ingestion of a glucose and triglyceride tolerance test meal (GTTTM) in which a panel of dietary fats with a gradual change in the ratio of MUFAs to SFAs was included. On 5 separate occasions, basal and postprandial concentrations of glucose, insulin, triglyceride, and free fatty acids (FFAs) were measured.

RESULTS

High-fat meals increased the postprandial concentrations of insulin, triglycerides, and FFAs, and they enhanced postprandial beta cell function while decreasing insulin sensitivity (as assessed with different model-based and empirical indexes: insulinogenic index, insulinogenic index/homeostasis model assessment of insulin resistance, area under the curve for insulin/area under the curve for glucose, homeostasis model assessment for beta cell function, and GTTTM-determined insulin sensitivity, oral glucose insulin sensitivity, and the postprandial Belfiore indexes for glycemia and blood FFAs. These effects were significantly ameliorated, in a direct linear relation, when MUFAs were substituted for SFAs.

CONCLUSIONS

The data presented here suggest that beta cell function and insulin sensitivity progressively improve in the postprandial state as the proportion of MUFAs with respect to SFAs in dietary fats increases.

Clinical significance of apolipoprotein A5

PURPOSE OF REVIEW

We have examined the evidence from recent human studies examining the role of apolipoprotein A-V in triglyceride-rich lipoprotein metabolism and cardiovascular disease risk. Special emphasis was placed on the evidence emerging from the association between genetic variability at the apolipoprotein A5 locus, lipid phenotypes and disease outcomes. Moreover, we address recent reports evaluating apolipoprotein A5 gene-environment interactions in relation to cardiovascular disease and its common risk factors.

RECENT FINDINGS

Several genetic association studies have continued to strengthen the position of APOA5 as a major gene that is involved in triglyceride metabolism and modulated by dietary factors and pharmacological therapies. Moreover, genetic variants at this locus have been significantly associated with both coronary disease and stroke risks.

SUMMARY

Apolipoprotein A-V has an important role in lipid metabolism, specifically for triglyceride-rich lipoproteins. However, its mechanism of action is still poorly understood. Clinical significance at present comes largely from genetic studies showing a consistent association with plasma triglyceride concentrations. Moreover, the effects of common genetic variants on triglyceride concentrations and disease risk are further modulated by other factors such as diet, pharmacological interventions and BMI. Therefore, these genetic variants could be potentially used to predict cardiovascular disease risk and individualize therapeutic options to decrease cardiovascular disease risk.

Increased Plasma Apolipoprotein C-III Concentration Independently Predicts Cardiovascular Mortality: The Hoorn Study

Background: Hypertriglyceridemia is a cardiovascular risk factor. Apolipoprotein C-III (apoC-III) is an important determinant of the catabolic rate of triglyceride-rich lipoproteins. The aim of this study was to investigate the prognostic value of plasma apoC-III concentrations for cardiovascular mortality.

Methods: We performed this prospective study in 2244 subjects (ages 49–77 years) who participated in the Hoorn Study. During a mean follow-up of 15 years, 504 individuals died: 231 of cardiovascular disease, 180 of cancer, and 93 of other causes. Cardiovascular disease risk factors and plasma apoC-III concentrations were measured at baseline.

Results: The age- and sex-adjusted plasma apoC-III concentration was prospectively associated with cardiovascular mortality (P &lt; 0.001). After adjustment for traditional risk factors, including fasting triglycerides, the hazard ratio (95% CI) for cardiovascular death between the highest and the lowest quartile of apoC-III was 1.85 (1.02–3.38). High concentrations of apoC-III did not appear to be associated with noncardiovascular mortality.

Conclusions: In this general population cohort, a high apoC-III concentration in plasma, independently of fasting triglycerides and other traditional risk factors, predicts cardiovascular mortality.

Methodology for studying postprandial lipid metabolism

BACKGROUND

Postprandial lipid metabolism in humans has deserved much attention during the last two decades. Although fasting lipid and lipoprotein parameters reflect body homeostasis to some extent, the transient lipid and lipoprotein accumulation that occurs in the circulation after a fat-containing meal highlights the individual capacity to handle an acute fat input. An exacerbated postprandial accumulation of triglyceride-rich lipoproteins in the circulation has been associated with an increased cardiovascular risk.

METHODS

The important number of studies published in this field raises the question of the methodology used for such postprandial studies, as reviewed.

RESULTS

Based on our experiences, the present review reports and discuss the numerous methodological issues involved to serve as a basis for further works. These aspects include aims of the postprandial tests, size and nutrient composition of the test meals and background diets, pre-test conditions, characteristics of subjects involved, timing of sampling, suitable markers of postprandial lipid metabolism and calculations.

CONCLUSION

In conclusion, we stress the need for standardization of postprandial tests.