Insulin sensitivity and carotid intima-media thickness: relationship between insulin sensitivity and cardiovascular risk study

Triglycerides to high density lipoprotein cholesterol ratio (TG/HDL), but not triglycerides and glucose product (TyG) index, is associated with arterial stiffness in prediabetes

AIMS

Prediabetes (preD) carries increased risk of cardiovascular (CV) events than normal-glucose-tolerance (NGT). Insulin resistance, a hallmark of preD, is closely linked to CV-risk, making its assessment crucial. Triglycerides-to-high-density-lipoprotein-cholesterol-ratio (TG/HDL) and triglycerides-and-glucose-product (TyG) have emerged as surrogate of insulin resistance. We aimed to evaluate the association of these indexes with CV-risk assessed through arterial stiffness in preD.

METHODS

377 individuals without diagnosis of diabetes underwent: (1) complete biochemistry and oral-glucose-tolerance-test; (2) CV-risk assessment through arterial stiffness (pulsed-wave-velocity - PWV - and augmentation-index - AugI) and intima-media-thickness (IMT). Participants were split according to current guidelines: NGT (n = 100), preD (n = 216), and newly-diagnosed-type-2-diabetes (ND-T2D) (n = 61).

RESULTS

TG/HDL and TyG were higher in preD than NGT, with no difference between preD and ND-T2D regarding TG/HDL. PreD showed higher PWV, AugI, and IMT than NGT. In preD group, after adjusting for major confounders, PWV was correlated with TG/HDL (β = 0.16; P = 0.03), but not with TyG, and there was a trend of association with HOMA-IR (β = 0.19, P = 0.07). In logistic regression, being in the higher tertile of TG/HDL was associated with higher PWV (odds-ratio 2.51, 95 %CI 1.01-6.29, P = 0.048).

CONCLUSIONS

In preD, TG/HDL was independently associated with PWV, suggesting its possible role as a simple, cost-effective tool for assessing CV risk.

Elevated triglyceride-glucose index as a predictor of carotid plaque incidence: Insights from a comprehensive meta-analysis

BACKGROUND

Early detection of carotid plaque (CP) can help reduce the burden of ASCVD in the general population. CP and triglyceride-glucose index (TyGi) are associated with insulin resistance.

OBJECTIVES

We performed a meta-analysis exploring the association of TyGi levels with the incidence of CP.

METHODS

A systematic search of PubMed, Scopus, and Google Scholar till September 2023 reporting TyGi and CP identified 67 studies, of which 13 met our study criteria. TyGi was assessed both categorically and continuously. Binary random-effects models used for pooled odds ratios (OR) with 95% confidence intervals (CI) and I2 statistic for heterogeneity.

RESULTS

Analyzed data from 163,792 patients with a mean age of 53 ± 8.9 years, primarily female (51.5%). Common comorbidities were hypertension (42.4%) followed by dyslipidemia (24.3%). Multivariable analysis showed that high vs. low TyGi quartile was associated with a higher risk of CP with unadjusted OR (1.82, 95% CI [1.5 - 2.21], p < 0.01; I² = 95.77, p < 0.01) and adjusted OR (1.3, 95% CI [1.16 - 1.46], p < 0.01; I² = 79.71, p < 0.01). Increasing TyGi also had a higher risk of CP with unadjusted OR (1.53, 95% CI [1.15 - 2.03], p < 0.01; I² = 98.48, p < 0.01) and adjusted OR (1.23, 95% CI [1.11 - 1.35], p < 0.01; I² = 89.82, p < 0.01). The association was validated by sensitivity analysis.

CONCLUSION

Our study indicates a higher risk of CP in patients with higher TyGi scores, underscoring its significance as a predictor for carotid atherosclerosis.

Factors associated with insulin resistance in a longitudinal study of Ugandan youth with and without HIV

Prospective investigations from sub-Saharan Africa on metabolic complications in youth with perinatally acquired HIV (PHIV) are lacking. We investigated the changes in insulin resistance in Ugandan PHIV on ART and uninfected controls and their relationship with inflammation, HIV, and cardiovascular disease (CVD) risk factors. Participants 10-18 years of age were included in a prospective study performed in Kampala, Uganda. We compared baseline and changes in insulin resistance (by HOMA-IR) and in markers of inflammation at baseline and 96 weeks. PHIVs were on ART with HIV-1 RNA level 400 copies/ml or less. Generalized Estimating Equation models were used to assess associations between HOMA-IR, and demographic as well as inflammatory markers. Of the 197 participants recruited at baseline (101 PHIV, 96 HIV-negative), 168 (89 PHIV, 79 HIV-negative) had measurements at 96 weeks. At baseline, median (Q1, Q3) age was 13 years (11,15), 53.5% were women, median CD4 + cell counts were 988 cells/μl (631, 1310). At baseline, HOMA-IR was significantly higher in PHIV than in controls ( P  = 0.03). HOMA-IR did not significantly change by week 96 in either group, and at 96 weeks, was similar between groups ( P  = 0.15). HOMA-IR was not associated with any inflammatory markers, or any specific ART. In longitudinal analysis, age and Tanner stage remained associated with higher HOMA-IR throughout the study period, after adjusting for HIV status. In this longitudinal cohort of virally suppressed PHIV in Uganda, PHIV have decreased insulin sensitivity compared to controls, however this difference does not persist through adolescence. ART and immune activation do not appear to affect glucose homeostasis in this population.

Risk factors for carotid plaque formation in type 2 diabetes mellitus

OBJECT

Patients with type 2 diabetes mellitus (T2DM) are at higher risk of developing atherosclerosis. Previous studies have analyzed the factors associated with diabetic macrovascular disease, although whether these factors are applicable to T2DM patients with carotid atherosclerosis remains unclear. Therefore, the aim of this study was to investigate the risk factors for the formation of carotid atherosclerotic plaque in hospitalized T2DM patients and to provide a theoretical basis for early prevention and treatment of carotid atherosclerosis in these patients.

METHODS

A total of 949 patients with T2DM were included in the study. Carotid ultrasound identified 531 patients with carotid atherosclerotic plaque. The waist-to-hip ratio (WHR), blood glucose, liver and kidney function, blood lipid profile, islet function, and other indicators were measured at the same time to identify the risk factors and predictive significance of T2DM carotid plaque.

RESULTS

The proportions of men, diabetes nephropathy (DN) and hypertension in T2DM patients with carotid plaque are higher than those without carotid plaque(P < 0.05). Age, duration of diabetes, WHR, Postprandial glucose (PPG), lipoprotein (a) [Lip (a)], carcinoembryonic antigen(CEA) and estimated glomerular filtration rate (eGFR) in T2DM patients with carotid plaque were higher than those without plaque (P < 0.05). Age, WHR, duration of diabetes, hypertension, males, and Lip (a) were independent risk factors for T2DM patients with carotid plaque. Age, WHR, duration of diabetes, and Lip (a) had a higher AUC to predict T2DM with carotid artery plaque (AUC: 0.750, 0.640, 0.678, 0.552 respectively; P all < 0.001). After constructing the logit (P) value of the above risk factors, the area under the ROC curve was 0.816 (0.789-0.842, P < 0.001).

CONCLUSION

Age, WHR, duration of diabetes, hypertension, males, and Lip (a) levels are the main risk factors for the formation of carotid plaque in T2DM patients. Combining the above risk factors provides a better prediction of carotid plaque formation in T2DM.

Associations Among Tooth Loss, Periodontitis, and Carotid Intima-Media Thickness: the Nagahama Study

AIMS

This study aimed to clarify the relationships among tooth loss, periodontal condition, and subclinical atherosclerosis from the aspect of intensity, extent, and duration of inflammation.

METHODS

This cross-sectional study included 9,778 people from the Nagahama Study, a large-scale, general population-based study conducted in Japan. The number of teeth and periodontal status, including the attachment level (AL) and pocket depth (PD) of representative teeth from six regions, were evaluated by dentists. The maximum intima-media thickness (IMT) of the common carotid artery was used as an index of atherosclerosis.

RESULTS

In the multivariate analysis adjusted for conventional risk factors, a large number of missing teeth (＜9 remaining teeth), which related to long-lasting inflammation indicative of the highest stage of periodontitis, was identified as an independent determinant of IMT in a general population (coefficient: 0.042; 95% confidence interval [CI]: 0.016 to 0.068). The presence of two or more regions with an AL ≥4 mm, which is indicative of the progressing, long-lasting stages of periodontal inflammation, was also independently associated with IMT (coefficient: 0.016; 95% CI: 0.004 to 0.028). On the contrary, PD, a measure of the early and reversible phases of periodontal inflammation, and loss of AL in the group without tooth loss were not significantly associated with IMT, because of the limited degree of accumulated periodontitis.

CONCLUSION

The present results suggest that the association between periodontitis and atherosclerosis depends on the inflammation intensity, extent, and duration.

Triglyceride-Glucose Index is Related to Carotid Artery Plaque in Railway Workers: A Cross-Sectional Study

Aim

China has the highest rail transportation density in the world. Compared to other occupational populations, railway workers in China face increased risk of chronic non-communicable diseases. This study aims to investigate the relationship between the triglyceride-glucose (TyG) index and carotid artery plaque (CAP) in a population of railway workers in southwest China.

Methods

The cross-sectional study was conducted among 3169 railway workers who were categorized into four groups based on TyG index quartiles. The presence of CAP was assessed using carotid Doppler ultrasound. Logistic regression and restricted cubic spline analyses were used to estimate the association between TyG index and CAP, and subgroup analyses were performed based on age, blood pressure, metabolic dysfunction-associated fatty liver disease (MAFLD), smoking, drinking, and physical activity.

Results

Participants with higher TyG index quartiles had a higher prevalence of CAP, with 11.63%, 14.11%, 20.20%, and 18.56% from the first to fourth quartile, respectively. The multi-adjusted logistic regression models showed a positive association between TyG index and the risk of CAP (odds ratio [OR]: 1.22, 95% confidence interval [CI]: 1.06-1.41) when treated as a continuous variable. When analyzed as a categorical variable with increasing TyG index tertiles, the risk of CAP substantially increased with ORs (95% CIs) of 1.22 (0.90-1.65) for the second quartile, 1.70 (1.27-2.28) for the third quartile, and 1.46 (1.08-1.98) for the fourth quartile compared to the lowest quartile. Restricted cubic spline revealed that the association gradually strengthened with the increase of the TyG index below 9.56.

Conclusion

TyG index was significantly associated with CAP, notably in populations with elevated quartiles of TyG index among railway workers. Monitoring the TyG index could be a useful risk management strategy for CAP in occupation population.

Joint effect of blood pressure and glycemic variation on the risk of cardiovascular morbidity and mortality in persons with type 2 diabetes

OBJECTIVE

Few studies have explored the association of visit-to-visit variation in blood pressure (BP) and glycemic factors with cardiovascular disease (CVD) morbidity and mortality. This study aimed to examine the independent and joint effect of visit-to-visit BP and glycemic variation on CVD morbidity and mortality in persons with T2DM.

METHODS

The present study consisted of two retrospective cohort studies. The Taiwan Diabetes Study was based on a database of the National Diabetes Care Management Program (DCMP) and linked with cardiovascular morbidity incidence. The Taichung Diabetes Study was based on the DCMP database of a medical center, which can be linked with the National Death Registry dataset. The outcomes were analyzed by using Cox's proportional hazard models.

RESULTS

A total of 13,280 and 10,894 persons with T2DM in Taiwan and Taichung Diabetes Study, respectively, were included. SBP-CV, FPG-CV, and HbA1c-CV were significant predictors of stroke, CVD event or death, all-cause mortality, and expanded CVD mortality, whereas DBP-CV was a significant predictor of all-cause mortality and expanded and non-expanded CVD mortality. The joint effect of SBP, FPG, and HbA1c predicted the incidence of stroke and CVD event or death with increased risks of 16 %-35 %. In addition, the joint effect of SBP, DBP, FPG, and HbA1c was associated with all-cause and expanded CVD mortality with increased risks of 29 %-81 %.

CONCLUSIONS

The joint effect of BP and glucose variation improved the prediction of cardiovascular morbidity and mortality. Moreover, simultaneous measurement of visit-to-visit BP and glycemic variation may stratify persons with cardiovascular risks and may be regarded as important therapeutic goals in the care of T2DM.

Distinct triglyceride-glucose trajectories are associated with different risks of incident cardiovascular disease in normal-weight adults

BACKGROUND

Long-term patterns of the triglyceride-glucose index (TyG index) and their effects on cardiovascular disease (CVD) among normal-weight adults are poorly characterized. This study aimed to identify TyG index trajectories in normal-weight adults and to determine their association with the risk of incident CVD.

METHODS

This study included 40,473 normal-weight participants who were free of stroke and myocardial infarction prior to or in 2012. The TyG index was calculated as ln (fasting triglyceride [mg/dL] × fasting glucose [mg/dL]/2), and the TyG index trajectories during 2006-2012 were identified by latent mixture modeling.

RESULTS

We identified five distinct TyG index trajectories according to TyG index range and changing pattern over time: low-stable (n = 9,806; mean TyG index 7.84-7.93), moderate-stable (n = 22,066; mean TyG index 8.43-8.52), high-decreasing (n = 1,469; mean TyG index 9.83-8.75), moderate-increasing (n = 5,842; mean TyG index 8.98-9.26), and high-stable (n = 1,290; mean TyG index 9.91-10.07). During 6.74 years of follow-up, we documented 1,577 incident CVD events. Compared with the low-stable pattern, the highest risk of CVD was observed in the high-stable pattern (hazard ratio [HR], 2.24; 95% confidence interval [CI]: 1.73-2.90), followed by the moderate-increasing pattern (HR, 1.70; 95% CI, 1.43-2.04), the high-decreasing pattern (HR, 1.45; 95% CI, 1.11-1.89), and the moderate-stable pattern (HR, 1.25; 95% CI, 1.08-1.44). Similar results were also observed for stroke and myocardial infarction.

CONCLUSIONS

Distinct TyG index trajectories were significantly associated differently subsequent risk of CVD in normal-weight individuals. These observations suggested that long-term trajectories of TyG index may be useful for predicting CVD among normal-weight adults.

A High Triglyceride-Glucose Index Value Is Associated With an Increased Risk of Carotid Plaque Burden in Subjects With Prediabetes and New-Onset Type 2 Diabetes: A Real-World Study

Background

The triglyceride-glucose (TyG) index has been proposed as a convincing indicator of insulin resistance and has been found to be associated with atherosclerosis among diabetic patients. However, the relationship between the TyG index and arteriosclerosis in subjects with prediabetes and new-onset type 2 diabetes (T2D) remains uncertain. The purpose of this study was to assess the degree of carotid plaque burden in patients with prediabetes and new-onset T2D and to investigate the association between the TyG index and the degree of carotid plaque burden in this population.

Methods

This was a cross-sectional observational study that included 716 subjects aged 40–70 years old with prediabetes or new-onset T2D. Demographic, anthropometric, and laboratory measurements were collected. Participants underwent carotid arteriosclerosis evaluation by ultrasonography, and the degree of atherosclerosis was evaluated according to the carotid plaque burden. The TyG index was calculated.

Results

The population was stratified into high or low TyG index groups according to the median TyG index value. Higher values were associated with a higher BMI and waist circumference as well as higher total cholesterol, triglyceride, low-density lipoprotein cholesterol, plasma glucose, glycated hemoglobin, fasting C-peptide, and C-reactive protein levels (P < 0.001). The high TyG index group had a higher atherosclerotic plaque burden than the low TyG index group (P < 0.001). Multiclassification logistic regression analysis showed that the TyG index was positively associated with a high plaque burden [odds ratio (OR): 16.706, 95% confidence interval (CI): 3.988–69.978, P = 0.000], while no association was found between the TyG index and a low/moderate plaque burden. This association remained consistent in the subgroup analysis. In multiple linear regression analysis, sex, age, and the TyG index were found to be independently associated with carotid plaque burden. For each unit increase in the TyG index, the risk of a high carotid plaque burden increased 1.595-fold.

Conclusion

A high TyG index was positively associated with a high carotid plaque burden in subjects with prediabetes and new-onset T2D. Clinicians should pay close attention to the TyG index to help these patients receive the greatest benefit from early intervention.

Effect of Arterial Stiffness and Carotid Intima-Media Thickness Progression on the Risk of Dysglycemia, Insulin Resistance, and Dyslipidemia: a Temporal Causal Longitudinal Study

BACKGROUND

We investigated the temporal causal longitudinal associations of carotid-femoral pulse wave velocity (cfPWV), a measure of arterial stiffness, and carotid intima-media thickness (cIMT) progression with the risk of dysglycemia, insulin resistance, and dyslipidemia.

METHODS

We included 3862, 17.7-year-old, participants from the Avon Longitudinal Study of Parents and Children, followed up for 7 years. cfPWV, cIMT, and fasting plasma samples were repeatedly measured. We computed homeostatic model assessment (HOMA) of insulin resistance and percent pancreatic beta-cell function. Data were analyzed using logistic regression, linear mixed-effect, and cross-lagged structural equation models.

RESULTS

A higher cfPWV at 17.7 years was associated with higher insulin at age 24.5 years (odds ratio, 1.25 [CI, 1.08-1.44]; P=0.003), which slightly attenuated after covariates adjustment. Higher cIMT at 17.7 years was associated with lower insulin (odds ratio, 0.06 [0.01-0.95]; P=0.046) at 24.5 years, after covariate adjustments. In mixed-effect models, the 7-year progression in cfPWV (predictor) was directly associated with the increase in triglyceride (outcome). cIMT progression was associated with the 7-year increase in LDL (low-density lipoprotein), triglyceride, and glucose. In cross-lagged models, higher cfPWV at 17.7 years was associated with higher insulin (β=0.06, SE, 0.12, P=0.014), HOMA of insulin resistance, and HOMA-percent pancreatic beta-cell function at 24.5 years. However, insulin, HOMA of insulin resistance, and HOMA-percent pancreatic beta-cell function at 17.7 years were not associated with cfPWV at 24.5 years. Higher cIMT at 17.7 years was associated with reduced insulin, HOMA of insulin resistance, and HOMA-percent pancreatic beta-cell function at 24.5 years, but not vice versa. Higher glucose at 17.7 years was associated with higher cfPWV and cIMT at 24.5 years only.

CONCLUSIONS

Arterial stiffness in adolescence may be a causal risk factor for hyperinsulinemia and insulin resistance in young adulthood.

Association between the triglyceride-glucose index and carotid plaque stability in nondiabetic adults

BACKGROUND AND AIMS

The rupture of an unstable atherosclerotic plaque is one of the major causes of thrombosis. However, there was limited evidence on the relationship of triglyceride-glucose (TyG) index, a simple surrogate marker of insulin resistance, with the carotid plaque stability. This study aimed to investigate the association between the TyG index and carotid plaque stability in nondiabetic adults.

METHODS AND RESULTS

The study included 4748 nondiabetic participants from the Asymptomatic Polyvascular Abnormalities Community study. Carotid plaque stability was assessed using ultrasonography. The TyG index was calculated as ln [fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2]. Logistic regression was used to evaluate the association of the TyG index with carotid plaque stability by calculating odds ratio (OR) and 95% confidence interval (CI). Of the 4748 participants, 1192 (25.11%) participants had stable carotid plaque, and 1247 (26.26%) had unstable carotid plaque. The prevalence of unstable carotid plaque substantially increased with increasing TyG index tertile (P for trend <0.0001). In the fully adjusted model, the OR comparing participants in the highest versus the lowest tertile of the TyG index was 1.31 (95% CI, 1.09-1.57). The optimal cutoff point for the TyG index in case of unstable carotid plaque was 8.56. However, we did not observe a statistically significant association between the TyG index and stable carotid plaque.

CONCLUSIONS

Elevated the TyG index was significantly associated with the prevalence of unstable carotid plaque in nondiabetic adults.

What Can We Change in Diet and Behaviour in Order to Decrease Carotid Intima-Media Thickness in Patients with Obesity?

Atherosclerosis-considered the major cause of cardiovascular diseases (CVDs)-is strongly associated with obesity, to which it strongly contributes. Moreover, atherosclerosis is characterised by a long asymptomatic phase, and its progression can lead to serious cardiovascular (CV) events. The carotid intima-media thickness (cIMT) has been determined as a predictor of CV events, as well as a marker of subclinical atherosclerosis, and has been used in clinical trials as an alternative assessment method or a surrogate endpoint. It should be noted that several behavioural approaches can directly influence the cIMT values, and decrease or increase the CV risk. In our paper, we aimed to summarize the current knowledge regarding IMT measurement among patients with obesity as a risk group-also in terms of the obesity paradox where the diagnosis of subclinical atherosclerosis is especially essential and implements the early therapeutic approach. We also summarized behavioural, modifiable factors, such as the Mediterranean diet, the Dietary Approach to Stop Hypertension Diets, body weight reduction or the intake of micro- and macronutrients, with a particular focus on the studies where the cIMT values were one of the outcomes. In order to collect the literature data related to the presented topic, the PubMed database was explored.

Association of Flow Parameters and Diameter in the Common Carotid Artery with Impaired Glucose Metabolism

AIM

Diameter, intima-media thickness (IMT), and flow parameters, including resistance index (RI) and pulsatility index (PI), in the common carotid artery (CCA) are markers of arterial remodeling, atherosclerosis, and vascular resistance, respectively. We investigated the differences among these markers in association with plasma glucose level, serum insulin level, and insulin resistance in participants without cardiovascular disease.

METHODS

CCA parameters (including the CCA interadventitial diameter and mean IMT at the time of 75-g oral glucose tolerance testing) were assessed in 4218 participants. RI and PI were assessed in 3380 of these participants. To assess plasma glucose and serum immunoreactive insulin profiles during oral glucose tolerance testing, we used the total areas under the curves (AUCglu and AUCins, respectively). We used the homeostasis model assessment of insulin resistance (HOMA-IR) and the Matsuda index to assess insulin resistance. Insulin secretion was assessed with the HOMA-β.

RESULTS

AUCglu was significantly associated with CCA interadventitial diameter (β=0.048, P＜0.001), RI (β=0.144, P＜0.001), and PI (β=0.103, P＜0.001) but not with mean IMT. AUCins (β=-0.064, P＜0.001) and HOMA-β (β=-0.054, P＜0.001) were significantly and negatively associated with CCA interadventitial diameter, but not with mean IMT. Both HOMA-IR and Matsuda index were significantly associated with RI and PI.

CONCLUSIONS

These findings indicate that all CCA parameters except IMT are associated with impaired glucose metabolism in patients without cardiovascular disease.

Non-Alcoholic Fatty Liver Disease: From Pathogenesis to Clinical Impact

Non-Alcoholic Fatty Liver Disease (NAFLD) is caused by the accumulation of fat in over 5% of hepatocytes in the absence of alcohol consumption. NAFLD is considered the hepatic manifestation of metabolic syndrome (MS). Recently, an expert consensus suggested as more appropriate the term MAFLD (metabolic-associated fatty liver disease). Insulin resistance (IR) plays a key role in the development of NAFLD, as it causes an increase in hepatic lipogenesis and an inhibition of adipose tissue lipolysis. Beyond the imbalance of adipokine levels, the increase in the mass of visceral adipose tissue also determines an increase in free fatty acid (FFA) levels. In turn, an excess of FFA is able to determine IR through the inhibition of the post-receptor insulin signal. Adipocytes secrete chemokines, which are able to enroll macrophages inside the adipose tissue, responsible, in turn, for the increased levels of TNF-α. The latter, as well as resistin and other pro-inflammatory cytokines such as IL-6, enhances insulin resistance and correlates with endothelial dysfunction and an increased cardiovascular (CV) risk. In this review, the role of diet, intestinal microbiota, genetic and epigenetic factors, low-degree chronic systemic inflammation, mitochondrial dysfunction, and endoplasmic reticulum stress on NAFLD have been addressed. Finally, the clinical impact of NAFLD on cardiovascular and renal outcomes, and its direct link with type 2 diabetes have been discussed.

Association between asymptomatic intracranial arterial stenosis and insulin resistance or diabetes mellitus: a cross-sectional study in rural Shandong, China

INTRODUCTION

Recent studies have shown that insulin resistance (IR) is correlated to atherosclerosis development. However, few studies have investigated the association between IR and asymptomatic intracranial arterial stenosis (aICAS).

RESEARCH DESIGN AND METHODS

This cross-sectional study enrolled 2007 rural residents in China who were aged ≥40 years without a clinical history of stroke and transient ischaemic attack. We used transcranial Doppler ultrasonography in combination with magnetic resonance angiography to diagnose aICAS (stenosis ≥50%). IR was defined as a homeostasis model assessment of insulin resistance ≥3.0 based on the 75th percentile for all the participants. Multivariate logistic regression models were employed to assess the relationship of diabetic parameters with aICAS in all participants, as well as with aICAS in non-diabetic participants, and further stratified by sex.

RESULTS

After adjusting for age, gender, smoking habit, drinking habit, low-density lipoprotein cholesterol, raised blood pressure, triglycerides, high-density lipoprotein cholesterol and waist circumference, diabetes mellitus (DM) (OR=2.09, 95% CI 1.31 to 3.32), fasting plasma glucose (FPG) (OR=1.34, 95% CI 1.14 to 1.57), and IR (OR=1.75, 95% CI 1.11 to 2.75) were associated with aICAS in the total study population; however, these relationships remained significant only in men after the analyses were stratified by sex (DM: OR=3.40, 95% CI 1.62 to 7.13; FPG: OR=1.64, 95% CI 1.26 to 2.13; IR: OR=3.04, 95% CI 1.44 to 6.42). When further excluding the diabetic participants from the total study population, positive associations between IR and aICAS were similarly observed only in men (OR=4.65, 95% CI 1.69 to 12.82).

CONCLUSIONS

IR might predict the prevalence of aICAS independently of major cardiovascular risk factors and metabolic syndrome components among men living in rural China.

Insulin Resistance and Atherosclerosis: Implications for Insulin-Sensitizing Agents

Patients with type 2 diabetes mellitus (T2DM) are at high risk for macrovascular complications, which represent the major cause of mortality. Despite effective treatment of established cardiovascular (CV) risk factors (dyslipidemia, hypertension, procoagulant state), there remains a significant amount of unexplained CV risk. Insulin resistance is associated with a cluster of cardiometabolic risk factors known collectively as the insulin resistance (metabolic) syndrome (IRS). Considerable evidence, reviewed herein, suggests that insulin resistance and the IRS contribute to this unexplained CV risk in patients with T2DM. Accordingly, CV outcome trials with pioglitazone have demonstrated that this insulin-sensitizing thiazolidinedione reduces CV events in high-risk patients with T2DM. In this review the roles of insulin resistance and the IRS in the development of atherosclerotic CV disease and the impact of the insulin-sensitizing agents and of other antihyperglycemic medications on CV outcomes are discussed.

Modifiable risk factors for carotid atherosclerosis: a meta-analysis and systematic review

Background

Carotid atherosclerosis is a major cause of stroke, but the conclusion about risk factors for carotid atherosclerosis is still controversial. The aim of our present meta-analysis and systematic review was to explore the modifiable risk factors for carotid atherosclerosis.

Methods

We searched PubMed from January 1962 to October 2018 to include longitudinal and cross-sectional studies. The results were pooled using random effects model. Heterogeneity was measured by I² statistic and publication bias was assessed by funnel plots.

Results

A total of 14,700 articles were screened, of which 76 with 27 factors were eligible. Our meta-analysis of cross-sectional studies indicated nine factors (hyperlipidemia, hyperhomocysteinemia, hypertension, hyperuricemia, smoking, metabolic syndrome, hypertriglyceridemia, diabetes, and higher low density lipoprotein) were significantly associated with the presence of carotid plaque, among which four (hyperlipidemia, hyperhomocysteinemia, hypertension, and hyperuricemia) could elevate the risk of atherosclerosis by at least 50%; and one factor (hypertension) was associated with increased carotid intima-media thickness. In the systematic review, another five factors [negative emotion, socioeconomic strain, alcohol, air pollution, and obstructive sleep apnea syndrome (OSAS)] were also related to the presence of atherosclerosis. The cross-sectional associations with most of the above 14 factors were further confirmed by longitudinal studies. Among them, the managements of 4 factors (hypertension, hyperlipidemia, diabetes and OSAS) were indicated to prevent carotid atherosclerosis by cohort studies.

Conclusions

Effective interventions targeting pre-existing disease, negative emotion, lifestyle and diet may reduce the risk of carotid atherosclerosis. Further good-quality prospective studies are needed to confirm these findings.

A Mitochondrial Approach to Cardiovascular Risk and Disease

BACKGROUND

Cardiovascular diseases (CVDs) are a leading risk factor for mortality worldwide and the number of CVDs victims is predicted to rise through 2030. While several external parameters (genetic, behavioral, environmental and physiological) contribute to cardiovascular morbidity and mortality; intrinsic metabolic and functional determinants such as insulin resistance, hyperglycemia, inflammation, high blood pressure and dyslipidemia are considered to be dominant factors.

METHODS

Pubmed searches were performed using different keywords related with mitochondria and cardiovascular disease and risk. In vitro, animal and human results were extracted from the hits obtained.

RESULTS

High cardiac energy demand is sustained by mitochondrial ATP production, and abnormal mitochondrial function has been associated with several lifestyle- and aging-related pathologies in the developed world such as diabetes, non-alcoholic fatty liver disease (NAFLD) and kidney diseases, that in turn can lead to cardiac injury. In order to delay cardiac mitochondrial dysfunction in the context of cardiovascular risk, regular physical activity has been shown to improve mitochondrial parameters and myocardial tolerance to ischemia-reperfusion (IR). Furthermore, pharmacological interventions can prevent the risk of CVDs. Therapeutic agents that can target mitochondria, decreasing ROS production and improve its function have been intensively researched. One example is the mitochondria-targeted antioxidant MitoQ10, which already showed beneficial effects in hypertensive rat models. Carvedilol or antidiabetic drugs also showed protective effects by preventing cardiac mitochondrial oxidative damage.

CONCLUSION

This review highlights the role of mitochondrial dysfunction in CVDs, also show-casing several approaches that act by improving mitochondrial function in the heart, contributing to decrease some of the risk factors associated with CVDs.

Association between insulin resistance and the development of cardiovascular disease

For many years, cardiovascular disease (CVD) has been the leading cause of death around the world. Often associated with CVD are comorbidities such as obesity, abnormal lipid profiles and insulin resistance. Insulin is a key hormone that functions as a regulator of cellular metabolism in many tissues in the human body. Insulin resistance is defined as a decrease in tissue response to insulin stimulation thus insulin resistance is characterized by defects in uptake and oxidation of glucose, a decrease in glycogen synthesis, and, to a lesser extent, the ability to suppress lipid oxidation. Literature widely suggests that free fatty acids are the predominant substrate used in the adult myocardium for ATP production, however, the cardiac metabolic network is highly flexible and can use other substrates, such as glucose, lactate or amino acids. During insulin resistance, several metabolic alterations induce the development of cardiovascular disease. For instance, insulin resistance can induce an imbalance in glucose metabolism that generates chronic hyperglycemia, which in turn triggers oxidative stress and causes an inflammatory response that leads to cell damage. Insulin resistance can also alter systemic lipid metabolism which then leads to the development of dyslipidemia and the well-known lipid triad: (1) high levels of plasma triglycerides, (2) low levels of high-density lipoprotein, and (3) the appearance of small dense low-density lipoproteins. This triad, along with endothelial dysfunction, which can also be induced by aberrant insulin signaling, contribute to atherosclerotic plaque formation. Regarding the systemic consequences associated with insulin resistance and the metabolic cardiac alterations, it can be concluded that insulin resistance in the myocardium generates damage by at least three different mechanisms: (1) signal transduction alteration, (2) impaired regulation of substrate metabolism, and (3) altered delivery of substrates to the myocardium. The aim of this review is to discuss the mechanisms associated with insulin resistance and the development of CVD. New therapies focused on decreasing insulin resistance may contribute to a decrease in both CVD and atherosclerotic plaque generation.

Renal function markers and insulin sensitivity after 3 years in a healthy cohort, the EGIR-RISC study

BACKGROUND

People with chronic renal disease are insulin resistant. We hypothesized that in a healthy population, baseline renal function is associated with insulin sensitivity three years later.

METHODS

We studied 405 men and 528 women from the European Group for the study of Insulin Resistance - Relationship between Insulin Sensitivity and Cardiovascular disease cohort. Renal function was characterized by the estimated glomerular filtration rate (eGFR) and by the urinary albumin-creatinine ratio (UACR). At baseline only, insulin sensitivity was quantified using a hyperinsulinaemic-euglycaemic clamp; at baseline and three years, we used surrogate measures: the Matsuda insulin sensitivity index (ISI), the HOmeostasis Model Assessment of Insulin Sensitivity (HOMA-IS). Associations between renal function and insulin sensitivity were studied cross-sectionally and longitudinally.

RESULTS

In men at baseline, no associations were seen with eGFR, but there was some evidence of a positive association with UACR. In women, all insulin sensitivity indices showed the same negative trend across eGFR classes, albeit not always statistically significant; for UACR, women with values above the limit of detection, had higher clamp measured insulin sensitivity than other women. After three years, in men only, ISI and HOMA-IS showed a U-shaped relation with baseline eGFR; women with eGFR> 105 ml/min/1.73m² had a significantly higher insulin sensitivity than the reference group (eGFR: 90-105 ml/min/1.73m²). For both men and women, year-3 insulin sensitivity was higher in those with higher baseline UACR. All associations were attenuated after adjusting on significant covariates.

CONCLUSIONS

There was no evidence to support our hypothesis that markers of poorer renal function are associated with declining insulin sensitivity in our healthy population.

Hepatic lipase inactivation decreases atherosclerosis in insulin resistance by reducing LIGHT/Lymphotoxin β-Receptor pathway

Coexistence of insulin resistance (IR) and metabolic syndrome (MetS) increases the risk of cardiovascular disease (CVD). Genetic studies in diabetes have linked Hepatic Lipase (HL) to an enhanced risk of CVD while others indicate a role of HL in inflammatory cells. Thus, we explored the role of HL on atherosclerosis and inflammation in a mouse model of MetS/IR, (apoE-/-Irs2+/- mice) and in patients with MetS and IR. HL-deficiency in apoE-/-Irs2+/- mice reduced atheroma size, plaque vulnerability, leukocyte infiltration and macrophage proliferation. Compared with apoE-/-Irs2+/-HL+/+ mice, MCP1, TNFa and IL6 plasma levels, pro-inflammatory Ly6Chi monocytes and activated(CD69+)-T lymphocytes were also decreased in apoE-/-Irs2+/-HL-/- mice. The LIGHT (Tumour necrosis factor ligand superfamily member 14, TNFSF14)/ Lymphotoxin β-Receptor(LTβ-R) pathway, which is involved in T-cell and macrophage activation, was diminished in plasma and in apoE-/-Irs2+/-HL-/- mouse atheromas. Treatment of apoE-/-Irs2+/-HL-/- mice with LIGHT increased the number of Ly6Chi-monocytes and lesion size. Acutely LIGHT-treated apoE-/- mice displayed enhanced proliferating Ly6Chi-monocytes and increased activation of the mitogen-activated protein kinase p38, suggesting that LIGHT/LTβ-R axis might promote atherogenesis by increasing proinflammatory monocytes and proliferation. Notably, MetS-IR subjects with increased atherosclerosis displayed up-regulation of the LIGHT/LTβ-R axis, enhanced inflammatory monocytes and augmented HL mRNA expression in circulating leukocytes. Thus, HL-deficiency decreases atherosclerosis in MetS/IR states by reducing inflammation and macrophage proliferation which are partly attributed to reduced LIGHT/LTβ-R pathway. These studies identify the LIGHT/LTβ-R axis as a main pathway in atherosclerosis and suggest that its inactivation might ameliorate inflammation and macrophage proliferation associated with atherosclerosis burden in MetS/IR.

Supplementary Material to this article is available at www.thrombosis-online.com.

Carotid Intima-medial Thickness and Glucose Homeostasis in Indian Obese Children and Adolescents

OBJECTIVE

To evaluate for subclinical atherosclerosis and its risk factors in Indian obese children.

MATERIALS AND METHODS

A cross-sectional, case-control study was conducted to recruit 80 children aged 6-17 years with constitutional obesity as cases and 23 age- and gender-matched controls with normal body mass index (BMI). Anthropometric and clinical evaluation was followed by biochemical analysis and body fat estimation by dual-energy X-ray absorptiometry in cases. Similar evaluation was performed for controls except laboratory parameters. Carotid intima-media thickness (CIMT) was measured with B-mode ultrasonography in both cases and controls to evaluate subclinical atherosclerosis.

RESULTS

The mean age of cases was 12.8 ± 3 years, with mean BMI of 29.2 ± 4.8 kg/m². The mean CIMT was significantly higher in cases than controls (0.54 ± 0.13 vs. 0.42 ± 0.08; P < 0.001 across all ages). CIMT was significantly higher in participants who were hypertensive than nonhypertensive (0.6 ± 0.11 vs. 0.53 ± 0.11 mm; P = 0.04). CIMT showed a positive correlation with BMI (r = 0.23, P = 0.02), percentage body fat and fat mass index (r = 0.28 and 0.3 respectively; P < 0.001), but not with waist: hip ratio. CIMT showed significant positive correlation with blood glucose at 60 min (r = 0.22; P = 0.04), serum insulin at 60 min (r = 0.28; P = 0.01) while negative correlation with whole body insulin sensitivity (r = -0.27; P = 0.01).

CONCLUSION

CIMT correlated significantly to blood pressure, insulin sensitivity, and body fat in Indian obese children.

Insulin resistance and β-cell function in smokers: results from the EGIR-RISC European multicentre study

AIMS

Tobacco smoking is known to increase the long-term risk of developing Type 2 diabetes mellitus, but the mechanisms involved are poorly understood. This observational, cross-sectional study aims to compare measures of insulin sensitivity and β-cell function in current, ex- and never-smokers.

METHODS

The study population included 1246 people without diabetes (mean age 44 years, 55% women) from the EGIR-RISC population, a large European multicentre cohort. Insulin sensitivity was measured using a hyperinsulinaemic, euglycaemic clamp and the homeostatic model assessment - insulin resistance (HOMA-IR) index. Two β-cell function parameters were derived from measures during an oral glucose tolerance test: the early insulin response index and β-cell glucose sensitivity. Additionally, the areas under the curve during the oral glucose tolerance test were calculated for glucose, insulin and C-peptide.

RESULTS

According to smoking habits, there were differences in insulin sensitivity, which was lower in women who smoked, and in β-cell glucose sensitivity, which was lower in men who smoked, but these associations lost significance after adjustment. However, after adjustment, the areas under the glucose and the C-peptide curves during the oral glucose tolerance test were significantly higher in men who smoked.

CONCLUSIONS

Smoking habits were not independently associated with insulin sensitivity or β-cell function in a healthy middle-aged European population. Health-selection bias, methodological shortcomings or a true lack of causal links between smoking and impaired insulin sensitivity/secretion are possible explanations. The mechanisms behind the observed increased glucose and C-peptide areas under the curve during the oral glucose tolerance test in male smokers need to be further evaluated.

Sulforaphane improves dysregulated metabolic profile and inhibits leptin-induced VSMC proliferation: Implications toward suppression of neointima formation after arterial injury in western diet-fed obese mice

Sulforaphane (SFN), a dietary phase-2 enzyme inducer that mitigates cellular oxidative stress through nuclear factor erythroid 2-related factor 2 (Nrf2) activation, is known to exhibit beneficial effects in the vessel wall. For instance, it inhibits vascular smooth muscle cell (VSMC) proliferation, a major event in atherosclerosis and restenosis after angioplasty. In particular, SFN attenuates the mitogenic and pro-inflammatory actions of platelet-derived growth factor (PDGF) and tumor necrosis factor-α (TNFα), respectively, in VSMCs. Nevertheless, the vasoprotective role of SFN has not been examined in the setting of obesity characterized by hyperleptinemia and insulin resistance. Using the mouse model of western diet-induced obesity, the present study demonstrates for the first time that subcutaneous delivery of SFN (0.5mg/Kg/day) for~3weeks significantly attenuates neointima formation in the injured femoral artery [↓ (decrease) neointima/media ratio by~60%; n=5-8]. This was associated with significant improvements in metabolic parameters, including ↓ weight gain by~52%, ↓ plasma leptin by~42%, ↓ plasma insulin by~63%, insulin resistance [↓ homeostasis model assessment of insulin resistance (HOMA-IR) index by~73%], glucose tolerance (↓ AUCGTT by~24%), and plasma lipid profile (e.g., ↓ triglycerides). Under in vitro conditions, SFN significantly decreased leptin-induced VSMC proliferation by~23% (n=5) with associated diminutions in leptin-induced cyclin D1 expression and the phosphorylation of p70S6kinase and ribosomal S6 protein (n=3-4). The present findings reveal that, in addition to improving systemic metabolic parameters, SFN inhibits leptin-induced VSMC proliferative signaling that may contribute in part to the suppression of injury-induced neointima formation in diet-induced obesity.

Diabetes Mellitus, Arterial Wall, and Cardiovascular Risk Assessment

Diabetes mellitus is an independent risk factor for atherothrombotic cardiovascular disease. Adults with diabetes are two to four times more likely to develop heart disease or stroke than adults without diabetes. The two major features of diabetes, i.e., hyperglycemia and insulin-resistance, trigger arterial stiffening and increase the susceptibility of the arterial wall to atherosclerosis at any given age. These pathological changes in the arterial wall may provide a functional and structural background for cardiovascular events. The present paper provides a critical overview of the clinical evidence linking diabetes-related metabolic abnormalities to cardiovascular risk, debates the pathophysiologic mechanisms through which insulin resistance and hyperglycemia may affect the arterial wall, and discusses the associations between vascular biomarkers, metabolic abnormalities and cardiovascular events.

Arterial stiffness, atherosclerosis and cardiovascular risk: Pathophysiologic mechanisms and emerging clinical indications

Arterial stiffness results from a degenerative process affecting mainly the extracellular matrix of elastic arteries under the effect of aging and risk factors. Changes in extracellular matrix proteins and in the mechanical properties of the vessel wall related to arterial stiffening may activate number of mechanisms involved also in the process of atherosclerosis. Several noninvasive methods are now available to estimate large artery stiffness in the clinical setting, including carotid-femoral pulse wave velocity, the reference for aortic stiffness estimate, and local distensibility measures of superficial arteries, namely carotid and femoral. An independent predictive value of arterial stiffness for cardiovascular events has been demonstrated in general as well as in selected populations, and reference values adjusted for age and blood pressure have been established. Thus, arterial stiffness is emerging as an interesting tissue biomarker for cardiovascular risk stratification and estimation of the individual "biological age". This paper overviews the mechanisms accounting for development and progression of arterial stiffness and for associations between arterial stiffness, atherosclerotic burden and incident cardiovascular events, summarizes the evidence and caveat for clinical use of stiffness as surrogate marker of cardiovascular risk, and briefly outlines some emerging methods for large artery stiffness characterization.

Carotid Intima-Media Thickness for Atherosclerosis

The carotid intima-media thickness (IMT) is a widely used surrogate marker for atherosclerosis worldwide. The carotid IMT can be simply, noninvasively, and reproducibly measured through B-mode carotid ultrasound. The carotid IMT is also a strong predictor of future cerebral and cardiovascular events. In addition, regressions of increased carotid IMT by lipid-lowering and antihypertensive drugs have been reported. Despite the strong association between increased carotid IMT and cardiovascular disease, it remains unclear whether routine carotid IMT measurement is useful for the detection of subclinical atherosclerosis in clinical practice. Researches should consider other methodological aspects, such as the definition of carotid plaques, the choice of measurement sites on the common or internal carotid artery, and the assessment of maximum or minimum IMT. The detailed guidelines for measuring carotid IMT vary by county. Thus, the usefulness of the carotid IMT may be assessed in different countries taking racial differences into account. Other important parameters revealed by carotid ultrasound, such as artery stenosis and the characteristics and size of plaques, should also be considered. Physicians should comprehensively interpret the results of carotid ultrasonography. Therefore, carotid ultrasonography is an essential tool for assessing cardiovascular risk in clinical settings.

Obesity and carotid artery remodeling

BACKGROUND/OBJECTIVE

The present study tested the hypothesis that obesity-related changes in carotid intima-media thickness (IMT) might represent not only preclinical atherosclerosis but an adaptive remodeling meant to preserve circumferential wall stress (CWS) in altered hemodynamic conditions characterized by body size-dependent increase in stroke volume (SV) and blood pressure (BP).

SUBJECTS/METHODS

Common carotid artery (CCA) luminal diameter (LD), IMT and CWS were measured in three different populations in order to study: (A) cross-sectional associations between SV, BP, anthropometric parameters and CCA LD (266 healthy subjects with wide range of body weight (24-159 kg)); (B) longitudinal associations between CCA LD and 3-year IMT progression rate (ΔIMT; 571 healthy non-obese subjects without increased cardiovascular (CV) risk); (C) the impact of obesity on CCA geometry and CWS (88 obese subjects without CV complications and 88 non-obese subjects matched for gender and age).

RESULTS

CCA LD was independently associated with SV that was determined by body size. In the longitudinal study, baseline LD was an independent determinant of ΔIMT, and ΔIMT of subjects in the highest LD quartile was significantly higher (28±3 μm) as compared with those in the lower quartiles (8±3, 16±4 and 16±3 μm, P=0.001, P<0.05 and P=0.01, respectively). In addition, CCA CWS decreased during the observational period in the highest LD quartile (from 54.2±8.6 to 51.6±7.4 kPa, P<0.0001). As compared with gender- and age-matched lean individuals, obese subjects had highly increased CCA LD and BP (P<0.0001 for both), but only slightly higher CWS (P=0.05) due to a significant increase in IMT (P=0.005 after adjustment for confounders).

CONCLUSIONS

Our findings suggest that in obese subjects, the CCA wall thickens to compensate the luminal enlargement caused by body size-induced increase in SV, and therefore, to normalize the wall stress. CCA diameter in obesity could represent an additional biomarker, depicting the impact of altered hemodynamics on arterial wall.

Impact of glucose-lowering drugs on cardiovascular disease in type 2 diabetes

Type 2 diabetes mellitus (T2DM) is characterized by multiple pathophysiologic abnormalities. With time, multiple glucose-lowering medications are commonly required to reduce and maintain plasma glucose concentrations within the normal range. Type 2 diabetes mellitus individuals also are at a very high risk for microvascular complications and the incidence of heart attack and stroke is increased two- to three-fold compared with non-diabetic individuals. Therefore, when selecting medications to normalize glucose levels in T2DM patients, it is important that the agent not aggravate, and ideally even improve, cardiovascular risk factors (CVRFs) and reduce cardiovascular morbidity and mortality. In this review, we examine the effect of oral (metformin, sulfonylureas, meglitinides, thiazolidinediones, DPP4 inhibitors, SGLT2 inhibitors, and α-glucosidase inhibitors) and injectable (glucagon-like peptide-1 receptor agonists and insulin) glucose-lowering drugs on established CVRFs and long-term studies of cardiovascular outcomes. Firm evidence that in T2DM cardiovascular disease can be reversed or prevented by improving glycaemic control is still incomplete and must await large, long-term clinical trials in patients at low risk using modern treatment strategies, i.e., drug combinations designed to maximize HbA1c reduction while minimizing hypoglycaemia and excessive weight gain.

Pharmacological activation of PPAR gamma ameliorates vascular endothelial insulin resistance via a non-canonical PPAR gamma-dependent nuclear factor-kappa B trans-repression pathway

Vascular endothelial insulin resistance (IR) is a critically initial factor in cardiocerebrovascular events resulted from diabetes and is becoming a worldwide public health issue. Thiazolidinediones (TZDs) are clinical insulin-sensitizers acting through a canonical peroxisome proliferator-activated receptor gamma (PPARγ)-dependent insulin trans-activation pathway. However, it remains elusive whether there are other mechanisms. In current study, we investigated whether TZDs improve endothelial IR induced by high glucose concentration or hyperglycemia via a non-canonical PPARγ-dependent nuclear factor-kappa B (NF-κB) trans-repression pathway. Our results showed that pre-treatment with TZDs dramatically decrease the susceptibility of endothelial cell to IR, while post-treatment notably improve the endothelial IR both in vitro and in vivo. Moreover, TZDs substantially increase the levels of endothelial nitric oxide synthase (eNOS) and inhibitory κB alpha (IκBα), whereas decrease those of the phosphorylated inhibitory κB kinase alpha/beta (phosphor-IKKα/β) and the cytokines including tumor necrosis factor alpha (TNFα), interleukin-6 (IL-6), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cellular adhesion molecule-1 (sVCAM-1), suggesting that TZDs act indeed through a PPARγ-dependent NF-κB trans-repression pathway. These findings highlighted a non-canonical mechanism for TZDs to ameliorate endothelial IR which might provide a potential strategy to prevent and treat the diabetic vascular complications clinically.

Contrasting associations of insulin resistance with diabetes, cardiovascular disease and all-cause mortality in the elderly: PROSPER long-term follow-up

AIMS/HYPOTHESIS

Insulin resistance is commonly proposed as a precursor to both type 2 diabetes and cardiovascular disease (CVD), yet few studies have directly compared insulin resistance with both outcomes simultaneously and determined whether associations with each outcome differ in strength or are comparable. We assessed the association of fasting insulin and HOMA-IR with incident CVD and diabetes in older people.

METHODS

In the long-term follow-up of the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER) cohort, HOMA-IR measurement was available in 4,742 older people (70-82 years) without diabetes at baseline. Of these, 283 developed diabetes during the 3.2 year within-trial follow-up, while 1,943 all-cause deaths, 470 CHD deaths (identified from death records) and 590 fatal/non-fatal CVD events (identified from medical record linkage in the Scottish participants) occurred during an extended 8.6 years of total follow-up. Cause-specific Cox proportional-hazards models were fitted using multivariable models.

RESULTS

Higher HOMA-IR was associated with incident diabetes: HR 4.80 (95% CI 3.14, 7.33) comparing extreme thirds after adjustment for confounders. However, HOMA-IR in the top third was not associated with all-cause mortality, CHD mortality or fatal/non-fatal CVD: HR 1.02 (95% CI 0.90, 1.17), 1.03 (0.79, 1.36) and 0.94 (0.74, 1.20), respectively. Results were similar when fasting insulin was considered as an exposure.

CONCLUSIONS/INTERPRETATION

Our data support insulin resistance as a predictor of diabetes in later life but, perhaps surprisingly, suggest this pathway is of negligible importance to CVD outcomes in the elderly.

Decision tree analysis of traditional risk factors of carotid atherosclerosis and a cutpoint-based prevention strategy

BACKGROUND

Reducing the exposure to risk factors for the prevention of cardio-cerebral vascular disease is a crucial issue. Few reports have described practical interventions for preventing cardiovascular disease in different genders and age groups, particularly detailed and specific cutpoint-based prevention strategies.

METHODS

We collected the health examination data of 5822 subjects between 20 and 80 years of age. The administration of medical questionnaires and physical examinations and the measurement of blood pressure, fasting plasma glucose (FPG) and blood lipids [total cholesterol (TC), triglycerides (TG), high density lipoprotein-cholesterol (HDL-C), and low density lipoprotein-cholesterol (LDL-C)] were performed by physicians. Carotid ultrasound was performed to examine the carotid intima-media thickness (CIMT), which was defined as carotid atherosclerosis when CIMT ≥0.9 mm. Decision tree analysis was used to screen for the most important risk factors for carotid atherosclerosis and to identify the relevant cutpoints.

RESULTS

In the study population, the incidence of carotid atherosclerosis was 12.20% (men: 14.10%, women: 9.20%). The statistical analysis showed significant differences in carotid atherosclerosis incidence between different genders (P<0.0001) and age groups (P<0.001). The decision tree analysis showed that in men, the most important traditional risk factors for carotid atherosclerosis were TC (cutpoint [CP]: 6.31 mmol/L) between the ages of 20-40 and FPG (CP: 5.79 mmol/L) between the ages of 41-59. By comparison, LDL-C (CP: 4.27 mmol/L) became the major risk factor when FPG ≤5.79 mmol/L. FPG (CP: 5.52 mmol/L) and TG (CP: 1.51 mmol/L) were the most important traditional risk factors for women between 20-40 and 41-59 years of age, respectively.

CONCLUSION

Traditional risk factors and relevant cutpoints were not identical in different genders and age groups. A specific gender and age group-based cutpoint strategy might contribute to preventing cardiovascular disease.

Evidence-based estimation of insulin resistance

Insulin resistance is a complex phenotype. Surrogate markers based on peripheral glucose and insulin (and in some cases NEFA) concentrations can provide, at best, moderate approximations to direct physiological measurements (Pearson r values 0.6-0.7). Where the focus is solely on insulin resistance, the evidence reviewed in the paper by Otten et al in this issue (DOI: 10.1007/s00125-014-3285-x ) suggests that surrogate markers based on fasting samples alone are as valid as those that require multiple samples and an oral glucose load. This provides an evidence base for simplifying the design of some clinical studies.

Carotid intima-media thickness is reduced 12 months after gastric bypass surgery in obese patients with type 2 diabetes or impaired glucose tolerance

AIM

To investigate whether Roux-en-Y gastric bypass surgery (RYGB) - an in vivo model for normalisation of hyperglycaemia - improves carotid intima-media thickness (IMT) in patients with type 2 diabetes (T2D)/impaired glucose tolerance (IGT) and normal glucose tolerance (NGT).

METHODS

Observational prospective study, 34 obese patients (T2D (n = 14)/IGT (n = 4), and NGT (n = 16)) were investigated before and six and 12months after RYGB.

RESULTS

Mean carotid IMT was significantly reduced 12months after RYGB in patients with T2D/IGT (-0.041 mm (95% CI -0.069; -0.012, p = 0.005)) but not in patients with NGT (-0.010 mm (-0.039; 0.020, p = 0.52)). The between-group difference was not significant (p=0.13). Twelve months after RYGB, patients with respectively T2D/IGT and NGT demonstrated changes in weight: -29.9 kg, p<0.001/-30.6 kg, p < 0.001, HbA1c: -0.7%, p < 0.001/-0.1%, p = 0.33, systolic blood pressure: -2 mmHg, p = 0.68/-10 mmHg, p = 0.01 and diastolic blood pressure: -8 mmHg, p = 0.003/-11 mmHg, p < 0.001. 80% of T2D patients terminated antihyperglycaemic medication.

CONCLUSION

Mean carotid IMT was significantly reduced 12months after RYGB in patients with T2D/IGT which provides evidence to support that the earliest atherosclerotic changes in the arterial wall are reversible. Although numerically different from the changes observed in patients with NGT, the between-group difference was not statistically significant.

Radix Astragali Improves Dysregulated Triglyceride Metabolism and Attenuates Macrophage Infiltration in Adipose Tissue in High-Fat Diet-Induced Obese Male Rats through Activating mTORC1-PPAR γ Signaling Pathway

Increased levels of free fatty acids (FFAs) and hypertriglyceridemia are important risk factors for cardiovascular disease. The effective fraction isolated from radix astragali (RA) has been reported to alleviate hypertriglyceridemia. The mechanism of this triglyceride-lowering effect of RA is unclear. Here, we tested whether activation of the mTORC1-PPARγ signaling pathway is related to the triglyceride-lowering effect of RA. High-fat diet-induced obese (DIO) rats were fed a high-fat diet (40% calories from fat) for 9-10 weeks, and 4 g/kg/d RA was administered by gavage. RA treatment resulted in decreased fasting triglyceride levels, FFA concentrations, and adipocyte size. RA treated rats showed improved triglyceride clearance and fatty acid handling after olive oil overload. RA administration could also decrease macrophage infiltration and expression of MCP-1 and TNFα, but it may also increase the expression of PPARγ in epididymal adipose tissue from RA treated rats. Consistently, expressions of PPARγ and phospho-p70S6K were increased in differentiated 3T3-L1 adipocytes treated with RA. Moreover, RA couldnot upregulate the expression of PPARγ at the presence of rapamycin. In conclusion, the mTORC1-PPARγ signaling pathway is a potential mechanism through which RA exerts beneficial effects on the disturbance of triglyceride metabolism and dysfunction of adipose tissue in DIO rats.