Endothelial dysfunction and serum fatty acid composition in patients with type 2 diabetes mellitus

Dietary source of saturated fat and percentage body fat of patients with type 2 diabetes mellitus: A cross-sectional study

BACKGROUND

The influence of dietary fat on the body fat of patients with diabetes is not well established. This cross-sectional study aimed to analyze the association between percentage body fat (PBF) and dietary sources of fat from the usual diet of patients with type 2 diabetes.

METHODS

Outpatients were submitted to PBF evaluation estimated by bioelectrical impedance. The patient's usual diet was assessed by a 3-day weighed diet record (WDR), and compliance was analyzed by comparing the protein intake estimated from the WDR and that from 24-hr urinary nitrogen output.

RESULTS

A total of 188 patients with type 2 diabetes (aged 62.5 ± 8.8 years; 57% female, body mass index [BMI] 29.3 ± 3.8 kg/m²) were analyzed and divided into groups with high and low PBF according to mean PBF (men: 26.6 ± 7.1%; women: 39.8 ± 5.9%). Patients with high PBF consumed an increased proportion of red meat (52.0% of total meat), processed meat (5.4%), and saturated fat from red meat (2.1% of energy) compared to low PBF individuals (42.3% [p = 0.036]; 3.0% [p = 0.010]; 1.5% of energy [p = 0.032], respectively). According to Poisson's regression, the consumption of red meat (PR = 1.008 [95% CI = 1.002-1.013]; p = 0.006) and the reuse of frying oil (PR = 1.670 [95% CI = 1.240-2.249]; p = 0.001) were associated with higher PBF. In the adjusted analysis, the upper tertile of processed meat intake was associated with higher PBF (PR = 1.522 [95% CI = 1.226-1.891]; p = 0.001) compared to the lower tertile.

CONCLUSIONS

The present study suggested that a higher ingestion of dietary sources of saturated fat was associated with high PBF in patients with type 2 diabetes.

Improvement of microvascular endothelial dysfunction induced by exercise and diet is associated with microRNA-126 in obese adolescents

OBJECTIVE

Microvascular endothelial dysfunction, which is at the early stage of atherosclerosis, precedes macrovascular endothelial dysfunction. The study is aimed to investigate the mechanism underlying the improvement of microvascular endothelial dysfunction by exercise and diet in obese adolescents.

METHODS

A quasi-randomized study was carried out with 2 cohorts: the experimental group (57 obese male adolescents; age: 15.38 ± 2.82 years, BMI: 33.21 ± 4.23 kg/m²) completed a 6-week exercise program with dietary intervention, and control group (10 normal weight adolescents; age: 15.38 ± 2.82 years, BMI: 23.21 ± 4.23 kg/m²) maintained sedentary. Clinical characteristics, circulating NO, ET-1 and microRNA-126 (miR-126) levels were measured before and after 6 weeks. The Reactive Hyperemia Index (RHI) was measured using EndoPAT-2000 system.

RESULTS

After 6-weeks intervention, obese adolescents' body circumferences and glucolipid metabolism are significantly improved. RHI (p < 0.01) and serum levels of NO/ET-1 (p < 0.01) are significantly increased, while microRNA-126 significantly decreased (p < 0.01). ΔMiR-126 were positive correlated with ΔBMI (r = 0.60, p < 0.01), ΔRHI (r = 0.69, p < 0.05), and ΔNO/ET-1 (r = -0.68, p < 0.05).

CONCLUSIONS

Combination of exercise and diet control can effectively improve glycolipid metabolism of obese adolescents, and thus their microvascular endothelial function, which might be related to changes in serum miRNA-126.

Low linolenic and linoleic acid consumption are associated with chronic kidney disease in patients with type 2 diabetes

Aim

This cross-sectional study aimed to assess the association of the fat content in the diet with Diabetic Kidney Disease (DKD) in patients with type 2 diabetes.

Methodology

Patients from the Diabetes research clinic at Hospital de Clínicas de Porto Alegre (Brazil) were consecutively recruited. The inclusion criterion was the diagnosis of type 2 diabetes. The exclusion criteria were as follows: body mass index >40 kg/m², heart failure, gastroparesis, diabetic diarrhea, dietary counseling by a registered dietitian during the previous 12 months, and inability to perform the weighed diet records (WDR). The dietary fatty acids (saturated, monounsaturated and polyunsaturated) consumption was estimated by 3-day WDR. Compliance with the WDR technique was assessed by comparison of protein intake estimated from the 3-day WDR and from the 24-h urinary nitrogen output performed on the third day of the WDR period. The presence of DKD was defined as urinary albumin excretion (UAE) ≥ 30 mg / 24 h or/and glomerular filtration rate (eGFR) <60 ml/min/1.73 m². Urinary albumin was measured twice and eGFR was estimated by using the CKD-EPI equation.

Results

A total of 366 patients were evaluated; of these, 33% (n = 121) had DKD. Multivariate analysis showed that the intake of linolenic acid was negatively associated with DKD (OR = 0.57; 95% CI 0.35–0.93; P = 0.024), adjusted for gender, smoking, cardiovascular disease, ACE inhibitors and/or angiotensin receptor blocker use, systolic blood pressure, fasting plasma glucose and HDL cholesterol. In a separate model, similar results were observed for linoleic acid, adjusting to the same co-variables (OR = 0.95; 95% CI 0.91–0.99; P = 0.006).

Conclusion

The lower intake of polyunsaturated fatty acids, especially linolenic and linoleic acid, is associated with chronic kidney disease in patients with type 2 diabetes.

Subclinical sleep apnoea and plasma levels of endothelin-1 among young and healthy adults

Objective

Obstructive sleep apnoea (OSA) is a risk factor for vascular disease and other adverse outcomes. These associations may be at least partly due to early endothelin-1 (ET-1)-mediated endothelial dysfunction (ED). Therefore, we assessed the relationships between subclinical sleep apnoea and plasma levels of ET-1.

Methods

We performed a population-based study among 1255 young and healthy adults aged 25–41 years. Cardiovascular disease, diabetes or a body mass index >35 kg/m² were exclusion criteria. Plasma levels of ET-1 were measured using a high-sensitivity, single-molecule counting technology. The relationships between subclinical sleep apnoea (OSA indices: respiratory event index (REI), oxygen desaturation index (ODI), mean night-time blood oxygen saturation (SpO₂)) and ET-1 levels were assessed by multivariable linear regression analysis.

Results

Median age of the cohort was 35 years. Median ET-1 levels were 2.9 (IQR 2.4–3.6) and 2.5 pg/mL (IQR 2.1–3.0) among patients with (n=105; 8%) and without subclinical sleep apnoea (REI 5–14), respectively. After multivariable adjustment, subclinical sleep apnoea remained significantly associated with plasma levels of ET-1 (β=0.13 (95% CI 0.06 to 0.20) p=0.0002 for a REI 5–14; β=0.10 (95% CI 0.03 to 0.16) p=0.003 for an ODI≥5). Every 1% decrease in mean night-time SpO₂ increased ET-1 levels by 0.1 pg/mL, an association that remained significant after multivariable adjustment (β=0.02 (95% CI 0.003 to 0.033) p=0.02).

Conclusions

In this study of young and healthy adults, we found that participants with subclinical sleep apnoea had elevated plasma ET-1 levels, an association that was due to night-time hypoxaemia. Our results suggest that ED may already be an important consequence of subclinical sleep apnoea.

Maternal Weight Gain Regulates Omega-3 Fatty Acids in Male, Not Female, Neonates

The fetus largely depends on maternal supply and placental transport for its source of long-chain polyunsaturated fatty acids (LCPUFAs), which are essential for proper neurological and cardiovascular development. Pregnancy complications such as diabetes reduces neonatal LCPUFA supply, but little is known of how fatty acid delivery is affected by maternal body type or weight gain in uncomplicated pregnancies. In a cross-sectional study of maternal-neonatal pairs at term, we sought to determine the effect of gestational weight gain on neonatal LCPUFA supply. Forty maternal-neonatal pairs of uncomplicated (no gestational hypertension or diabetes) term pregnancies were recruited upon admission to Oregon Health & Science University Labor & Delivery for scheduled cesarean section. Maternal and umbilical cord plasma fatty acid profiles were measured using gas chromatography-mass spectrophotometry. First trimester weight gain was negatively correlated with maternal n-3 LCPUFA ( r = -0.80, P = .0002), and this was not affected by fetal sex. High maternal weight gain in the first trimester was negatively associated with cord n-3 polyunsaturated fatty acid levels ( r = -0.70, P = .03) and placental thickness ( r = -0.69, P = .03) in male, but not female, offspring. High maternal weight gain in the first trimester is associated with a thinner placenta and low levels of n-3 LCPUFA in male offspring. Further study is required to confirm that male offspring are at a higher risk of poor outcomes associated with high maternal weight gain early in pregnancy.

Synergistic association of elevated serum free fatty acid and glucose levels with large arterial stiffness in a general population: The Nagahama Study

BACKGROUND

Previous studies have reported that artificial increases in circulating free fatty acid (FFA) levels might have adverse effects on the vasculature. However, whether or not this effect can be extrapolated to physiological variations in FFA levels has not been clarified. Given that FFAs exert a lipotoxic effect on pancreatic β-cells and might directly damage the arterial endothelium, we hypothesized that these adverse effects might synergize with hyperglycemia.

METHODS

A total of 9396 Japanese subjects were included in the study. Serum FFA levels were measured at baseline examination. Brachial-to-ankle pulse wave velocity (baPWV) was measured as an index of arterial stiffness.

RESULTS

As serum levels of FFA were markedly lower in subjects with higher insulin level, a significant association between FFA levels and baPWV was observed only in subjects with blood samples taken under fasting (≥12 h, P<0.001) or near-fasting (5-11 h, P<0.001) conditions, and not in those taken under non-fasting (<5 h, P=0.307) conditions. Although type 2 diabetes and HbA1c showed a strong association with baPWV, the association between FFA level and baPWV remained significant (β=0.052, P<0.001) after adjustment for glycemic levels. In addition to their direct relationship, FFA and glucose levels were synergistically associated with baPWV (FFA(⁎)glucose; β=0.036, P<0.001). Differences in baPWV between the lowest and highest subgroups divided by a combination of FFA and glucose reached approximately 300 cm/s.

CONCLUSIONS

Physiological variations in FFA concentrations might be a risk factor for large arterial stiffness. FFA and hyperglycemia exert a synergistic adverse effect on the vasculature.

From rest to stressed: endothelin-1 levels in young healthy smokers and non-smokers

INTRODUCTION

Endothelin-1 (ET-1) is a potent vasoconstrictor produced by vascular endothelial cells, and a known marker of endothelial dysfunction. However, the acute and chronic effects of smoking and nicotine gum on the ET-1 response to acute physical stress in young healthy smokers have not been investigated.

METHODS

Healthy smokers (n=35) and non-smokers (n=35) underwent an exercise test to exhaustion (maximal oxygen consumption) on a treadmill. Smokers were assessed a) after 12h smoking abstinence (termed chronic smoking), b) immediately after smoking one cigarette (termed acute smoking), and c) immediately after chewing nicotine gum. Blood was drawn immediately pre-exercise, and 3 minutes post-exercise. During exercise, cardiorespiratory parameters were obtained breath-by-breath using an automated metabolic cart. Plasma ET-1 levels were quantified using enzyme-linked immunosorbent-assay. The above protocol was designed to incorporate exercise as a vascular stressor to reveal changes that would not be detected at rest.

RESULTS

Mean age was 28.6±7.2 years and body mass index (BMI) was 23.6±3.2 kg/m(2). Post-exercise ET-1 levels were significantly lower than pre-exercise levels in non-smokers (P<0.001) and smokers under all three conditions (P=0.005, P<0.001, P=0.001, respectively). There were no differences in post-exercise ET-1 levels between non-smokers and smokers under all three conditions, however the absolute and relative decrease in ET-1 levels was significantly smaller in chronic smokers compared with non-smokers (P=0.007 and P=0.004). Chronic smokers had a significantly lower exercise-induced change in tidal volume (P=0.050), fraction of expired CO2 (P=0.021), oxygen consumption (P=0.005), carbon dioxide elimination (P=0.004) and peak expiratory flow (P=0.003) compared with non-smokers. Furthermore, the decrease in ET-1 observed in non-smokers in response to exercise was significantly associated with exercise induced-changes in inspiratory time, time for a tidal volume cycle, respiratory frequency, inspired minute ventilation and peak inspiratory flow.

CONCLUSIONS

An acute decrease of circulating ET-1 in response to acute maximal exercise in young healthy individuals was noted. Chronic smokers had a significantly diminished decrease in ET-1 compared with non-smokers, however there were no significant differences in the ET-1 response between smokers under the three smoking conditions. Smokers were not able to achieve the same exercise-induced changes in cardiorespiratory parameters as non-smokers. By incorporating exercise as a vascular stressor in our study, we have taken a novel approach to provide evidence of an altered ET-1 and cardiorespiratory response that would not otherwise be observed at rest in young active healthy smokers.

Dietary fat composition and cardiac events in patients with type 2 diabetes

OBJECTIVE

To evaluate associations of dietary fat composition with the development of cardiac events in patients with type 2 diabetes, without ischemic heart disease who were followed for at least 12 months.

METHODS

In this prospective cohort study the usual diet of patients was retrospectively assessed by a 3-day weighed diet record (WDR). Compliance with the WDR technique was assessed by comparing protein intake estimated from 3-day WDR and 24-h urinary nitrogen output. The following were considered cardiac events: myocardial infarction, myocardial revascularization procedures, congestive heart failure, new-onset angina pectoris, and sudden death.

RESULTS

A total of 227 patients with type 2 diabetes (aged 59 ± 10 years; 46.0% male), were followed during 4.6 years. In a multivariate Cox regression analysis, the intake of polyunsaturated fatty acids had a protective effect for cardiac events (HR = 0.31, 95% CI: 0.11-0.89; P = 0.03) adjusted for age, gender, duration of diabetes, smoking, compliance with WDR, using hypolipidemic agents, and the presence of hypertension and diabetic nephropathy. When the fat intake was divided into quartiles, the highest intake of α-linolenic acid (>1.25% of energy) was negatively associated with cardiac events (HR = 0.58, 95% CI: 0.39-0.85; P = 0.006), adjusted for the same covariates..

CONCLUSION

In patients with type 2 diabetes without ischemic heart disease, a high intake of polyunsaturated fatty acids, especially alpha linolenic acid, was protective for the development of cardiac events..

Epigallocatechin gallate attenuates ET-1-induced contraction in carotid artery from type 2 diabetic OLETF rat at chronic stage of disease

AIMS

There is a growing body of evidence suggesting that epigallocatechin gallate (EGCG), a major catechin isolated from green tea, has several beneficial effects, such as anti-oxidant and anti-inflammatory activities. However, whether treatment with EGCG can suppress the endothelin-1 (ET-1)-induced contraction in carotid arteries from type 2 diabetic rats is unknown, especially at the chronic stage of the disease. We hypothesized that long-term treatment with EGCG would attenuate ET-1-induced contractions in type 2 diabetic arteries.

MAIN METHODS

Otsuka Long-Evans Tokushima fatty (OLETF) rats (43 weeks old) were treated with EGCG (200 mg/kg/day for 2 months, p.o.), and the responsiveness to ET-1, phenylephrine (PE), acetylcholine (ACh) and sodium nitroprusside (SNP) was measured in common carotid artery (CA) from EGCG-treated and -untreated OLETF rats and control Long-Evans Tokushima Otsuka (LETO) rats.

KEY FINDINGS

In OLETF rats, EGCG attenuated responsiveness to ET-1 in CA compared to untreated groups. However, EGCG did not alter PE-induced contractions in CA from OLETF rats. In endothelium-denuded arteries, EGCG did not affect ET-1-induced contractions in either the OLETF or LETO group. Acetylcholine-induced relaxation was increased by EGCG treatment in CA from the OLETF group. The expressions of ET receptors, endothelial nitric oxide synthase, superoxide dismutases, and gp91(phox) [an NAD(P)H oxidase component] in CA were not altered by EGCG treatment in either group.

SIGNIFICANCE

Our data suggest that, within the timescale investigated here, EGCG attenuates ET-1-induced contractions in CA from type 2 diabetic rats, and one of the mechanisms may involve normalizing endothelial function.

Vasoregulatory peptides pro-endothelin-1 and pro-adrenomedullin are associated with metabolic syndrome in the population-based KORA F4 study

BACKGROUND

Metabolic alterations and endothelial dysfunction are interrelated processes in type 2 diabetes (T2D) and metabolic syndrome (MetS) that often develop in parallel. We assessed the association of vasoactive precursor peptides (VPPs) with MetS and T2D.

DESIGN AND METHODS

Plasma levels of C-terminal pro-endothelin-1 (CT-proET-1) and midregional pro-adrenomedullin (MR-proADM) were measured by novel sensitive assays in 1590 participants of the population-based KORA F4 study. The association of the VPPs with T2D, MetS defined by IDF criteria, the components of MetS, and insulin resistance (IR) was assessed in logistic regression models.

RESULTS

Elevated levels of CT-proET-1 and MR-proADM were associated with T2D, MetS, and IR in age- and sex-adjusted models. After adjustment for age, sex, former vascular complications, lifestyle factors, high-sensitive C-reactive protein, and serum creatinine, significant associations with MetS were found for MR-proADM (OR=5.94, 95% CI 3.78-9.33) and CT-proET-1 (OR=5.18, 95% CI 3.48-7.71) (top quartile vs bottom quartile). CT-proET-1 and MR-proADM were strongly associated with all components of MetS as defined by IDF criteria. After multivariable adjustment, association of CT-proET-1 and MR-proADM with pathological glucose tolerance and T2D disappeared and a borderline association with IR was found only for CT-proET-1 (OR=1.34, 95% CI 0.96-1.87).

CONCLUSIONS

We here demonstrate for the first time that plasma levels of both MR-proADM and CT-proET-1 levels are related to MetS and its components, thus suggesting that they possibly have a role as a surrogate biomarker for the disease and its complications.

Fatty acid composition of adipose tissue triglycerides after weight loss and weight maintenance: the DIOGENES study

Fatty acid composition of adipose tissue changes with weight loss. Palmitoleic acid as a possible marker of endogenous lipogenesis or its functions as a lipokine are under debate. Objective was to assess the predictive role of adipose triglycerides fatty acids in weight maintenance in participants of the DIOGENES dietary intervention study. After an 8-week low calorie diet (LCD) subjects with > 8 % weight loss were randomized to 5 ad libitum weight maintenance diets for 6 months: low protein (P)/low glycemic index (GI) (LP/LGI), low P/high GI (LP/HGI), high P/low GI (HP/LGI), high P/high GI (HP/HGI), and a control diet. Fatty acid composition in adipose tissue triglycerides was determined by gas chromatography in 195 subjects before the LCD (baseline), after LCD and weight maintenance. Weight change after the maintenance phase was positively correlated with baseline adipose palmitoleic (16:1n-7), myristoleic (14:1n-5) and trans-palmitoleic acid (16:1n-7t). Negative correlation was found with baseline oleic acid (18:1n-9). Lower baseline monounsaturated fatty acids (14:1n-5, 16:1n-7 and trans 16:1n-7) in adipose tissue triglycerides predict better weight maintenance. Lower oleic acid predicts lower weight decrease. These findings suggest a specific role of monounsaturated fatty acids in weight management and as weight change predictors.

[Critical analysis of the American Diabetes Association dietary recommendations for cardiovascular disease in diabetes mellitus]

Cardiovascular disease (CVD) is the main cause of mortality among patients with diabetes mellitus (DM), and dietary intervention is an essential measure to prevent and treat this complication. The aim of this manuscript was to review scientific evidence that underlies the dietetic recommendations of the American Diabetes Association (ADA) for prevention and treatment of CVD in patients with DM. The ADA guidelines are mostly based on studies performed on patients with CVD and without DM. The evidence-based dietary recommendations for patients with DM are to increase the intake of fish and soluble fibers. Although DM has been considered as an equivalent of established CVD, the adoption of the same dietary recommendations for patients without DM and with CVD for all patients with DM is still questionable -- especially considering the peculiarities of CVD in DM. Randomized clinical trials including patients with DM should provide further information regarding the benefits of these dietary interventions for CVD.

Serum palmitic acid-oleic acid ratio and the risk of coronary artery disease: a case-control study

Serum free fatty acids are risk factors for future coronary artery disease (CAD). We investigated the association between serum palmitic acid (PA)-oleic acid (OA) ratio and CAD risk in a case-control (n=108/129) study. The PA-OA ratio was associated with future CAD events independently of standard lipid values. The PA-OA ratio was significantly associated with the risk of fatal CAD [odds ratio (OR): 60.4; 95% confidence interval (CI): 11.5-316.9; P<.001] while inversely associated in nonfatal CAD group (OR: 0.11; 95% CI: 0.02-0.53; P<.01), and no distinct modification by sex was found. Receiver-operating characteristic (ROC) analysis found that PA-OA ratio did as well as triglyceride (TG) and apolipoprotein B (apo B)-high-density lipoprotein cholesterol (HDLC) ratio at discriminating fatal CAD (area under ROC, TG, 0.692; apo B-HDLC, 0.683; PA-OA, 0.768, P<.001), and had similar effect with HDLC at discriminating nonfatal CADs (area under ROC, HDLC, 0.649; PA-OA, 0.659, P<.01).These findings suggested that PA-OA ratio did as well as and even better than traditional risk factors and arteriography examination in discriminating fatal and nonfatal CAD events. Serum PA-OA ratio could be a new factor for CAD risk assessment and prediction.

Papel dos lipídeos da dieta na nefropatia diabética

O objetivo do presente manuscrito foi revisar o possível papel dos lipídeos dietéticos na nefropatia diabética (ND), considerando as alterações do perfil lipídico associadas e a interação entre aspectos dietéticos e genéticos. Os lipídeos dietéticos podem ter um papel importante no desenvolvimento e na progressão da ND. A composição das gorduras da dieta tem sido associada com a ND, particularmente à microalbuminúria e às anormalidades lipídicas e de função endotelial. Entretanto, ainda não está comprovado o benefício da modificação da ingestão de gorduras em pacientes com ND, em especial sobre desfechos definitivos, como incidência e progressão da ND, insuficiência renal e morte. Além disso, a resposta do perfil lipídico à ingestão de gorduras pode ser influenciada por fatores genéticos. A identificação de polimorfismos genéticos específicos associados a essa interação poderá permitir a individualização de estratégias nutricionais na ND.