Asymptomatic hyperglycaemia is associated with increased intimal plus medial thickness of the carotid artery

Endothelial Dysfunction in Diabetes Mellitus: New Insights

Endothelial dysfunction (ED) is an important marker of future atherosclerosis and cardiovascular disease, especially in people with diabetes. This article summarizes the evidence on endothelial dysfunction in people with diabetes and adds different perspectives that can affect the presence and severity of ED and its consequences. We highlight that data on ED in type 1 diabetes are lacking and discuss the relationship between ED and arterial stiffness. Several interesting studies have been published showing that ED modulates microRNA, microvesicles, lipid levels, and the endoplasmatic reticulum. A better understanding of ED could provide important insights into the microvascular complications of diabetes, their treatment, and even their prevention.

Time in Range Does Not Associate With Carotid Artery Wall Thickness and Endothelial Function in Type 1 Diabetes

BACKGROUND

Patients with Type 1 diabetes (T1D) have an increased risk of developing atherosclerosis and complications as myocardial infarction and peripheral artery disease. The thickening of the carotid wall and the brachial artery dysfunction are early and preclinical manifestations of atherosclerosis. The standard marker of care for assessment of glycemic control, glycated hemoglobin, does not associate with early atherosclerosis. We have hypothesized that the emerging metric of glycemic control, as the time spent in the target range (TIR), might be associated with carotid thickening and endothelial dysfunction. According to the hypothesis, we have designed the present research with the aim to evaluate the association between TIR collected in the short and long term and the measures of arterial morphology and function in patients with T1D.

METHODS

In our study, 70 patients and 35 healthy controls underwent ultrasound vascular study to measure carotid artery intima-media thickness (IMT) and brachial artery endothelial function by the flow-mediated dilation (FMD) technique. TIR was collected by a continuous glucose monitoring system for 2 weeks, 3 months, and 6 months before the vascular study.

RESULTS

Patients with T1D showed a significantly higher carotid IMT (mean±SE, 644±19 vs. 568±29 µ; p= 0.04) and a significantly lower FMD (mean±SE, 7.6±0.4 vs. 9.8±0.6%; p=0.01) compared with control subjects. No significant relationship between IMT, FMD, and TIR collected in the short and long term emerged.

CONCLUSIONS

Young patients with T1D have early vascular abnormalities. The percent of TIR does not correlate with preclinical atherosclerosis. This finding underlines the complexity of the interplay between diabetes and atherosclerosis.

Artificial Intelligence Uncovered Clinical Factors for Cardiovascular Events in Myocardial Infarction Patients with Glucose Intolerance

PURPOSE

Glucose intolerance (GI), defined as either prediabetes or diabetes, promotes cardiovascular events in patients with myocardial infarction (MI). Using the pooled clinical data from patients with MI and GI in the completed ABC and PPAR trials, we aimed to identify their clinical risk factors for cardiovascular events.

METHODS

Using the limitless-arity multiple testing procedure, an artificial intelligence (AI)-based data mining method, we analyzed 415,328 combinations of < 4 clinical parameters.

RESULTS

We identified 242 combinations that predicted the occurrence of hospitalization for (1) percutaneous coronary intervention for stable angina, (2) non-fatal MI, (3) worsening of heart failure (HF), and (4) all causes, and we analyzed combinations in 1476 patients. Among these parameters, the use of proton pump inhibitors (PPIs) or plasma glucose levels > 200 mg/dl after 2 h of a 75 g oral glucose tolerance test were linked to the coronary events of (1, 2). Plasma BNP levels > 200 pg/dl were linked to coronary and cardiac events of (1, 2, 3). Diuretics use, advanced age, and lack of anti-dyslipidemia drugs were linked to cardiovascular events of (1, 3). All of these factors were linked to (4). Importantly, each finding was verified by independently drawn Kaplan-Meier curves, indicating that the determined factors accurately affected cardiovascular events.

CONCLUSIONS

In most previous MI patients with GI, progression of GI, PPI use, or high plasma BNP levels were linked to the occurrence of coronary stenosis or recurrent MI. We emphasize that use of AI may comprehensively uncover the hidden risk factors for cardiovascular events.

Plasma BNP Levels and Diuretics Use as Predictors of Cardiovascular Events in Patients with Myocardial Infarction and Impaired Glucose Tolerance

PURPOSE

Although impaired glucose tolerance (IGT) promotes cardiovascular events, our Alpha-glucosidase-inhibitor Blocks Cardiac Events in Patients with Myocardial Infarction and Impaired Glucose Tolerance (ABC) study showed that alpha-glucosidase inhibitors do not prevent cardiovascular events in patients with myocardial infarction (MI) and IGT. The aim of the present study was to identify potential clinical factors for cardiovascular events in patients with MI and IGT.

METHODS

Using the limitless-arity multiple testing procedure, an artificial intelligence (AI)-based data mining method, we analyzed 385,391 combinations of fewer than four clinical parameters.

RESULTS

We identified 380 combinations predicting the occurrence of (1) all-cause hospitalization, (2) hospitalization due to worsening of heart failure (HF), (3) hospitalization due to non-fatal MI, and (4) hospitalization due to percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) for stable angina among 385,391 combinations in 853 patients. Among these, either plasma BNP levels ≥ 200 pg/dl or diuretic use exclusively predicted (1) all-cause hospitalization, (2) hospitalization due to worsening of HF, and (3) hospitalization due to a non-fatal MI, with plasma BNP levels ≥ 200 pg/dl being the sole predictor of hospitalization due to PCI and CABG. Importantly, each finding was verified by independently drawn Kaplan-Meier curves, revealing the unexpected role of plasma BNP levels in the progression of coronary stenosis determined as the necessity of PCI and CABG for stable angina.

CONCLUSIONS

In patients with MI and IGT, high plasma BNP levels predicted the occurrence of coronary stenosis, recurrent MI, and worsening of HF, whereas diuretic use did not predict the progression of coronary stenosis but non-fatal MI and worsening of HF.

Endothelial dysfunction and intima media thickness are selectively related to the different carbohydrate disturbances across the glucose continuum

Aim: The aim of the present study was to investigate the prevalence of macrovascular complications across different carbohydrate disturbances. Patients and methods: In the study, we included 167 patients, divided them into three age and BMI matched groups - group 1 with obesity without carbohydrate disturbances (n = 66), group 2 with prediabetes (n = 68) and group 3 with newly diagnosed type 2 diabetes (n = 33). Endothelial function was evaluated using EndoPAT, intima media thickness (IMT) was measured on the common carotid artery and ankle-brachial index (ABI) was calculated. Results: The patients with T2D had significantly higher mean IMT than the other two groups. The best predictors of increased IMT were fasting blood glucose followed by age and SBP. ROC-analysis showed that blood glucose on 60 min of OGTT had a very good predictive value for endothelial dysfunction. Conclusions: Patients with newly diagnosed diabetes have increased IMT and a tendency towards higher ABI compared to normoglycemic and prediabetic subjects.

Clinical utility of carotid ultrasonography: Application for the management of patients with diabetes

Carotid ultrasonography is a non-invasive, simple and inexpensive modality to assess the severity of atherosclerosis. This article reviews related articles, summarizes the rationale for the application of carotid ultrasonography in clinical practice, and addresses the features and the limitations of carotid ultrasonography in cardiovascular risk prediction. Numerous large studies have confirmed that various carotid ultrasound measures, such as carotid intima-media thickness, the presence or absence of carotid plaque, plaque number and plaque area, can be independent predictors of cardiovascular diseases in individuals with and without diabetes mellitus. Furthermore, many studies showed that the use of carotid intima-media thickness (especially maximum intima-media thickness, including plaque thickness) and/or carotid plaque in addition to traditional risk factors significantly improved the prediction of the occurrence of cardiovascular diseases, while controversy remains. Several studies showed that the progression of carotid intima-media thickness also can be a surrogate end-point of cardiovascular events. However, the accumulated evidence has not been sufficient. Further study with sufficient power should be carried out. As plaque disruption, which plays a crucial role in the pathogenesis of cardiovascular events, is dependent on the content of lipid in the atheroma and the thickness of the fibrous cap, tissue characterization of a plaque might be useful for determining its fragility. Interestingly, recent studies have shown that ultrasonic tissue characterization of carotid lesions could improve the prediction ability of future cardiovascular diseases. Thus, carotid ultrasonography is a useful modality for better clinical practice of atherosclerosis in patients with diabetes.

Subclinical vascular disease in patients with diabetes is associated with insulin resistance

Patients with diabetes experience increased cardiovascular risk that is not fully explained by deficient glycemic control or traditional cardiovascular risk factors such as smoking and hypercholesterolemia. Asymptomatic patients with diabetes show structural and functional vascular damage that includes impaired vasodilation, arterial stiffness, increased intima-media thickness and calcification of the arterial wall. Subclinical vascular injury associated with diabetes predicts subsequent manifestations of cardiovascular disease, such as ischemic heart disease, peripheral artery disease and stroke. Noninvasive detection of subclinical vascular disease is commonly used to estimate cardiovascular risk associated to diabetes. Longitudinal studies in normotensive subjects show that arterial stiffness at baseline is associated with a greater risk for future hypertension independently of established risk factors. In patients with type 2 diabetes, vascular disease begins to develop during the latent phase of insulin resistance, long before the clinical diagnosis of diabetes. In contrast, patients with type 1 diabetes do not manifest vascular injury when they are first diagnosed due to insulin deficiency, as they lack the preceding period of insulin resistance. These findings suggest that insulin resistance plays an important role in the development of early vascular disease associated with diabetes. Cross-sectional and prospective studies confirm that insulin resistance is associated with subclinical vascular injury in patients with diabetes, independently of standard cardiovascular risk factors. Asymptomatic vascular disease associated with diabetes begins to occur early in life having been documented in children and adolescents. Insulin resistance should be considered a therapeutic target in order to prevent the vascular complications associated with diabetes.

Upregulation of miR-221 and -222 in response to increased extracellular signal-regulated kinases 1/2 activity exacerbates neointimal hyperplasia in diabetes mellitus

BACKGROUND AND AIMS

Diabetes is associated with accelerated arterial intimal thickening that contributes to the increased cardiovascular disease seen in this population. In healthy arteries, intimal thickening is inhibited by elevated levels of the cyclin-dependent kinase inhibitor, p27^Kip1, and intimal thickening is promoted by activation of the mammalian Target of Rapamycin to promote degradation of p27^Kip1 protein. Recently, we reported that two microRNAs, miR-221 and -222, which promote intimal thickening via down-regulation of mRNA encoding p27^Kip1, are elevated in the arteries of diabetic patients. To determine if these miRNAs are critical to the increased intimal thickening under diabetic conditions, we examined the regulation of p27^Kip1in a mouse model of diabetes.

METHODS

Comparisons of p27^Kip1 signaling in NONcNZO10 mice fed a diabetogenic versus control diet were performed using immunochemistry and real-time PCR.

RESULTS

Vascular smooth muscle cells and arteries of diabetic mice exhibited decreased levels of p27^Kip1 that derived from destabilization of p27^Kip1 mRNA in an extracellular signal response kinase-1/2 (ERK-1/2) dependent manner. The activity of ERK-1/2 is increased in the arteries of diabetic mice and promotes an increase in miR-221 and -222. Inhibition of miR-221 and -222 restores normal levels of p27^Kip1 mRNA and protein in the arteries of diabetic mice and reduces intimal thickening following wire injury.

CONCLUSIONS

These data suggest diabetes is accompanied by increases in arterial miR-221 and -222 expression that promotes intimal thickening. Inhibition of the increased miR-221 and -222 may be efficacious in the prevention of the cardiovascular complications of diabetes.

Exendin-4 protects HUVECs from t-BHP-induced apoptosis via PI3K/Akt-Bcl-2-caspase-3 signaling

AIMS

Although the insulinotropic role of glucagon-like peptide-1 (GLP-1) in type 2 diabetes mellitus has been substantiated, its role in cardioprotection remains largely unknown. In this study, we explored the effect and mechanism of exendin-4 on tert-butyl hydroperoxide (t-BHP)-induced apoptosis in human umbilical vein endothelial cells (HUVECs).

METHODS

HUVECs were treated with 100 µmol/L t-BHP for 4 h, following pretreatment with 2.5-25 nmol/L exendin-4. Cell viability was determined using an dimethyl thiazolyl diphenyl tetrazolium salt (MTT) assay. The percentage of apoptotic cells was determined by fluorescence microscopy after Hoechst/PI staining. Expression of cysteine-aspartic acid protease-3(caspase-3), beta-cell lymphoma 2(Bcl-2), protein kinase B(AKT), and phosphorylated AKT was detected by western blotting.

RESULTS

Exendin-4 reduced the percentage of cells undergoing apoptosis when HUVECs were exposed to t-BHP. Exendin-4 downregulated caspase-3 activity and increased Bcl-2 protein levels in t-BHP-treated HUVECs. These exendin-4-mediated effects were blocked in the presence of an inhibitor of phosphoinositide-3 kinase (PI3K). Exendin-4 reversed t-BHP-mediated inhibition of Akt phosphorylation, which was abrogated by the PI3K inhibitor, wortmannin.

CONCLUSION

Our findings suggest that exendin-4 reduces t-BHP-induced apoptosis of HUVECs. Additionally, PI3K/Akt-Bcl-2-caspase-3 signaling is involved in the exendin-4-mediated modulation of HUVECs.

Serum chemerin and high-sensitivity C reactive protein as markers of subclinical atherosclerosis in Egyptian patients with type 2 diabetes

CONTEXT

Chemerin is one of the adipokines that regulate fat metabolism. High-sensitivity C-reactive protein (hs-CRP) may be considered as a cardiovascular risk predictor. Measuring intima-media thickness of the CCA (C-IMT) is a well-evidenced tool for the detection of early stages of atherosclerosis. We aimed here to study both serum chemerin and hs-CRP as markers of subclinical atherosclerosis in Egyptian patients with type 2 diabetes, who are angiographically free of coronary artery disease (CAD).

SUBJECTS AND METHODS

This cross-sectional study was conducted on 180 subjects divided into two groups: Group A included 90 type 2 diabetic patients without CAD and group B including 90 nondiabetic control subjects. All study subjects were having normal coronary angiography. Serum chemerin, homeostasis model assessment for insulin resistance (HOMA-IR), glycated haemoglobin (HbA1c), lipid profile, hs-CRP as well as C-IMT were assessed in all study subjects.

RESULTS

There was a statistically significant difference between the 2 groups regarding serum chemerin level, HOMA-IR, hs-CRP and C-IMT; being higher in the diabetic patients than in the control group (p = 0.006, 0.024, 0.040 and <0.001, respectively). There was positive correlation between serum chemerin level and waist-to-hip ratio (WHR), HOMA-IR, hs-CRP and C-IMT. Carotid intima-media thickness was positively correlated with patients' WHR, blood pressure, HbA1c, diabetes duration as well as hs-CRP, and negatively correlated with ankle-brachial index (ABI). Linear regression analysis showed that HbA1c, serum chemerin and hs-CRP were independently affecting C-IMT. Serum hs-CRP was positively correlated with HbA1c and HOMA-IR (p = 0.006 and 0.032, respectively), and negatively correlated with HDL-cholesterol level (p = 0.018).

CONCLUSION

Both serum chemerin and hs-CRP could be considered as markers of subclinical atherosclerosis, and hence, may be utilized for the early detection of macrovascular disease, in Egyptian patients with type 2 diabetes.

Retrospective analysis of the relationship between elevated plasma levels of TXNIP and carotid intima-media thickness in subjects with impaired glucose tolerance and early Type 2 diabetes mellitus

AIMS

Accelerated atherosclerosis is the major cause of mortality in diabetic patients and increased oxidative stress probably plays an important role in its development. The aim of our study was to evaluate the relationship between thioredoxin-interacting protein (TXNIP) as an oxidative stress parameter and carotid artery intima-media thickness (CIMT) as an indicator of atherosclerosis in patients with early-state diabetes and impaired glucose tolerance.

METHODS

The study was a retrospective analysis of 90 patients with impaired glucose regulation (IGR), 80 patients with early Type 2 diabetes mellitus (T2DM), and 80 subjects with normal glucose tolerance (NGT) as the control group. It was conducted at the endocrine out-patient clinic and hospital department of Cangzhou Central Hospital (Cangzhou, China) from June 2012 to Oct. 2013. Plasma TXNIP was measured to evaluate the level of oxidative stress. CIMT was assessed by carotid artery ultrasonography. Soluble vascular cell adhesion molecule-1 (sVCAM-1), a risk indicator for endothelial dysfunction, was also measured.

RESULTS

Compared to the NGT control, patients with IGR showed significantly higher plasma levels of TXNIP (P<0.05). Compared to the IGR group, patients with T2DM also had significantly higher plasma levels of TXNIP (P<0.05). CIMT was significantly higher in the subjects with abnormal glucose metabolism than in the NGT group (P<0.05). CIMT showed positive correlations with both TXNIP and sVCAM-1 levels (r = 0.56 and r = 0.49, respectively, both P<0.01).

CONCLUSIONS

The present study showed that plasma levels of TXNIP may be a useful predictor of subclinical atherosclerosis in Type 2 diabetic patients.

Arterial stiffness and carotid intima-media thickness in diabetic peripheral neuropathy

Background

We investigated the relationship between peripheral neuropathy and parameters of arterial stiffness and carotid intima media thickness (CIMT) in patients with type 2 diabetes mellitus (T2DM).

Material/Methods

The study included 161 patients (80 females and 81 males), 69 of whom had peripheral neuropathy. All patients underwent 24-h blood pressure monitoring, and arterial stiffness parameters were measured. The CIMT was measured using B-mode ultrasonography and patients also underwent transthoracic echocardiographic examination.

Results

Patients with peripheral neuropathy, compared with those without it, were older (54.68±8.35 years vs. 51.04±7.89 years; p=0.005) and had T2DM for longer periods (60 vs. 36 months; p=0.004). Glycated hemoglobin (HbA1c) values (8.55±1.85 mg/dL vs. 7.30±1.51 mg/dL; p<0.001), pulse wave velocity (PWV) (7.74±1.14 m/s vs. 7.15±1.10 m/s; p=0.001), CIMT (anterior 0.74±0.15 mm vs. 0.67±0.13 mm; p=0.01), and left ventricular mass (LVM) index (98.68±26.28 g/m²vs. 89.71±19.70 g/m²; p=0.02) were all significantly increased in the group with peripheral neuropathy compared to the group without peripheral neuropathy. We determined that duration of diabetes, HbA1c, and LVM index were predictors of peripheral neuropathy.

Conclusions

A significant relationship was found between diabetic neuropathy and increased PWV, a parameter of arterial stiffness, as well as CIMT, a marker of systemic atherosclerosis. Diabetic peripheral neuropathy may be a determinant of subclinical atherosclerosis in T2DM.

Predictors of deterioration of glucose tolerance and effects of lifestyle intervention aimed at reducing visceral fat in normal glucose tolerance subjects with abdominal obesity

Aims/Introduction:  The aim of the present study was to determine the predictors of deterioration of glucose tolerance in individuals with normal glucose tolerance (NGT) and abdominal obesity, and whether a lifestyle intervention to reduce visceral fat is effective in these individuals.

Materials and Methods:  The study subjects were 251 individuals who had abdominal obesity with certain risk factors (hypertension, high fasting plasma glucose (FPG), elevated hemoglobin A_1c (HbA_1c), dyslipidemia and hyperuricemia) and underwent oral glucose tolerance test (OGTT) in 2004 and 2005.

Results:  Using the area under the receiver operating characteristic curve, we found that PG at 0 min, 60 min, and area under the curve (AUC) of glucose from 0 to 120 min (AUC [glucose_0–120]) in OGTT were significant predictors of deterioration of glucose tolerance, with optimal cut‐off values of 95 mg/dL, 158 mg/dL and 271 mg h/dL, respectively. Although the rate of deterioration of glucose tolerance didn’t decrease with reductions in visceral fat area (VFA) over the 1‐year period in subjects with NGT, the rate tended to decrease with reductions in VFA in high‐risk NGT subjects (PG at 0 min > 95 or at 60 min > 158, or AUC [glucose_0–120] > 271).

Conclusions:  These results suggest that reduction of visceral fat over 1 year might not be beneficial in all subjects with NGT, but is beneficial in high‐risk NGT. We propose that individuals with values of the aforementioned predictors higher than the cut‐off levels, even those with NGT, should receive a lifestyle intervention program aimed at reducing visceral fat to prevent deterioration of glucose tolerance. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00080.x, 2011)

Association between circulating leukocyte subtype counts and carotid intima-media thickness in Japanese subjects with type 2 diabetes

Background

An increased leukocyte count is an independent risk factor for cardiovascular events, but the association between leukocyte subtype counts and carotid atherosclerosis in patients with diabetes has not been determined. We therefore investigated the correlation between leukocyte subtype counts and intima-media thickness of the common carotid artery (CCA-IMT) in subjects with type 2 diabetes.

Methods

This cross-sectional study involved 484 in-patients with type 2 diabetes (282 males and 202 females), who were hospitalized for glycemic control and underwent carotid ultrasonography at Kumamoto University Hospital between 2005 and 2011. Mean and maximum CCA-IMT was measured by high-resolution B-mode ultrasonography.

Results

Univariate analyses revealed that mean CCA-IMT was positively correlated with age, systolic blood pressure, brachial-ankle pulse wave velocity (PWV), urinary albumin excretion and duration of diabetes, but was negatively correlated with diastolic blood pressure and fasting plasma glucose. Maximum CCA-IMT was positively and negatively correlated with the same factors as mean CCA-IMT except for fasting plasma glucose. Mean CCA-IMT was positively correlated with total leukocyte (r = 0.124, p = 0.007), monocyte (r = 0.373, p < 0.001), neutrophil (r = 0.139, p = 0.002) and eosinophil (r = 0.107, p = 0.019) counts. Maximum CCA-IMT was positively correlated with total leukocyte (r = 0.154, p < 0.001), monocyte (r = 0.398, p < 0.001), neutrophil (r = 0.152, p < 0.001) and basophil counts (r = 0.102, p = 0.027). Multiple regression analyses showed that monocyte count, age and PWV were significant and independent factors associated with mean CCA-IMT (adjusted R² = 0.239, p < 0.001), and that monocyte count, age and urinary albumin excretion were significant and independent factors associated with maximum CCA-IMT (adjusted R² = 0.277, p < 0.001).

Conclusions

Monocyte counts were positively correlated with both mean CCA-IMT and maximum CCA-IMT in patients with type 2 diabetes. Monocyte count may be a useful predictor of macrovascular complications in patients with type 2 diabetes.

Trial registration

Trial registry no: UMIN000003526.

Carotid ultrasonography: A potent tool for better clinical practice in diagnosis of atherosclerosis in diabetic patients

Cardiovascular disease (CVD) remains the main cause of death in diabetic patients, and once it has developed, diabetic patients have a worse outcome as compared with non‐diabetic patients. One reason for this is the difficulty of early diagnosis of atherosclerotic change in these patients. Although cardiovascular risk assessment based on conventional risk factors is recommended for predicting cardiovascular risk, validation studies showed only moderate performance. In contrast, it is unrealistic to screen for subclinical or silent atherosclerosis by sophisticated modalities, such as myocardial perfusion scintigraphy, coronary computed tomography angiography or conventional angiography in all diabetic patients, as these tests are limited by the potential of significant adverse effects, technical difficulty, availability and high cost. Therefore, a non‐invasive and inexpensive tool for risk prediction of subclinical atherosclerosis is required for identifying individuals at high risk of CVD. Recently, a number of studies have shown close associations between carotid atherosclerosis and cerebrovascular or coronary artery disease. Carotid ultrasonography has allowed clinicians to visualize the characteristics of the carotid wall and lumen surfaces to quantify the severity of atherosclerosis. Carotid intima‐media thickness (IMT) is an especially useful marker of the progression of atherosclerosis throughout the body, and is an excellent predictor of cardiovascular events. As a simple and non‐invasive procedure, measurement of carotid IMT is one of the most appropriate screening methods to specify high‐risk individuals in subjects with and without diabetes. Therefore, it is expected that carotid ultrasonography will become a potent tool for better clinical practice of atherosclerosis in diabetic patients.

Age- and gender-specific prevalence of carotid atherosclerosis and its association with metabolic syndrome in Hangzhou, China

OBJECTIVE

Because of rapid alterations in lifestyle and the incidence of metabolic syndrome (MetS), the prevalence of carotid atherosclerosis (CA) and carotid plaque (CP) may increase in China. We aimed to evaluate the prevalence of CA and CP as well as its relation to MetS in an East Chinese population.

METHODS

The study included 6142 subjects who underwent general health screening including carotid ultrasonography in 2009. Diagnoses of MetS were made according to the revised Adult Treatment Panel III criteria.

RESULTS

The prevalence of CA and CP increased gradually with age. These conditions were more prevalent in men than in women (CA: 22.1%vs 12.0%, P < 0.001; CP: 12.6%vs 7.2%, P < 0.001). Multivariate logistic regression analysis showed that male gender, age, blood pressure, fasting blood glucose (FBG) and low-density lipoprotein cholesterol were risk factors for CA and CP, while high-density lipoprotein cholesterol was protective for CA. Age ≥ 50 years has the largest impact on CA and CP, followed by elevated blood pressure and elevated blood glucose. Individuals with MetS had a higher prevalence of CA (27.7%vs 20.0% in men, 24.0%vs 10.3% in women; P < 0.001 in both) and CP (16.6%vs 11.2% in men, P < 0.001; 11.8%vs 6.5% in women, P < 0.005) than those without MetS. The prevalence and odds ratios of CA and CP aggregated with an increasing number of MetS components, even in individuals exhibiting only one component.

CONCLUSIONS

These results indicate that CA and CP have become a major public health problem in China. MetS and its components were associated with an increased prevalence of CA and CP.

Association of metabolic syndrome with carotid atherosclerosis in the young North Indian population

BACKGROUND

Metabolic syndrome (MetS) and its components are associated with increased risk of stroke and cardiovascular disease. Relationship of MetS to carotid atherosclerosis has not been documented well in North Indian population.

AIMS

(1) To determine the incidence of metabolic syndrome in asymptomatic healthy young North Indian population; (2) to evaluate individuals with MetS patients for carotid atherosclerosis by carotid duplex ultrasound examination; (3) to determine the significance of each component of MetS in relation to carotid atherosclerosis in these patients.

METHODS

440 individuals in the age group of 25-50 years, asymptomatic for cardiac or cerebrovascular disease were screened for metabolic syndrome. 162 patients from a hospital-based population fulfilled the criteria for MetS (as per NCEP ATP III criteria). Duplex ultrasound (DU) examination of extracranial carotid vessels was performed on all the subjects. 112 age- and sex-matched controls were screened, and they underwent DU examination for comparison.

RESULTS

Hypertriglyceridemia was the commonest component seen in 79.6% of the MetS subjects, followed by central obesity seen in 74.6% subjects. Carotid atherosclerotic disease was observed in 21.6% of patients with MetS. Mild atherosclerosis (intima media thickness (IMT) >0.09 cm) was observed in 82.8% and 17.3% had plaques with mild stenosis (<50%) in the extracranial carotid arteries. Among patients of MetS with carotid atherosclerotic disease 82.6% had hypertriglyceridemia and 71.5% had 4 or more components for MetS. Among controls, five subjects (4.46%) had evidence of mild carotid atherosclerosis (IMT >0.09 cm) on DU. MetS was significantly associated with carotid DU abnormalities (increased IMT >0.09 cm) compared to controls (Fischer's exact test p<0.0001). Univariate analysis showed the relationship of hypertriglyceridemia to carotid atherosclerosis (p=0.03). On multivariate regression analysis none of the individual components of MetS contributed significantly to the presence of carotid atherosclerosis.

CONCLUSIONS

MetS is common in asymptomatic healthy North Indian population, with hypertriglyceridemia being the commonest component of MetS in this population, which may be predictive of carotid atherosclerotic disease. Serum triglyceride estimation can serve as a screen for asymptomatic healthy subjects to select the target population for cerebrovascular disease prevention.

Carotid intima-media thickness as a surrogate marker of cardiovascular disease in diabetes

BACKGROUND

Diabetes mellitus is associated with a high risk of cardiovascular disease. Carotid intima-media thickness (CIMT) is increasingly used as a surrogate marker for atherosclerosis. Its use relies on its ability to predict future clinical cardiovascular end points.

METHODS

This review examines the evidence linking CIMT as a surrogate marker of vascular complications in people with type 1 and type 2 diabetes. We have also reviewed the various treatment strategies which have been shown to influence CIMT.

CONCLUSIONS

CIMT measurement is an effective, noninvasive tool which can assist in identifying people with diabetes who are at higher risk of developing microvascular and macrovascular complications. It may also help to evaluate the effectiveness of various treatment strategies used to treat people with diabetes.

Role of reactive oxygen species in the progression of type 2 diabetes and atherosclerosis

Type 2 diabetes is the most prevalent and serious metabolic disease all over the world, and its hallmarks are pancreatic beta-cell dysfunction and insulin resistance. Under diabetic conditions, chronic hyperglycemia and subsequent augmentation of reactive oxygen species (ROS) deteriorate beta-cell function and increase insulin resistance which leads to the aggravation of type 2 diabetes. In addition, chronic hyperglycemia and ROS are also involved in the development of atherosclerosis which is often observed under diabetic conditions. Taken together, it is likely that ROS play an important role in the development of type 2 diabetes and atherosclerosis.

Adiposity is associated with endothelial activation in healthy 2-3 year-old children

Adiposity is associated with C-reactive protein level in healthy 2-3 year-old children and with other markers of endothelial activation in adults, but data are lacking in very young children. Data from 491 healthy Hispanic children were analyzed. Mean age was 2.7 years (SD 0.5, range 2-3 years); mean body mass index (BMI) was 17.2 kg/m2 (SD 1.9) among boys and 17.1 kg/m2 (SD 2.1) among girls. E-selectin level was associated with BMI (R = 0.11; p < 0.02), ponderal index (p < 0.02), waist circumference (p = 0.02), fasting insulin (p < 0.02), and insulin resistance (p < or = 0.05); these associations remained significant after adjustment for age, sex and fasting glucose. sVCAM was also associated with BMI (R = 0.12; p < 0.05). These observations indicate that adiposity is associated with inflammation and endothelial activation in very early childhood.

Impaired glucose tolerance is a risk factor for stroke in a Japanese sample--the Funagata study

Impaired glucose tolerance (IGT) is a known risk factor for cardiovascular disease, which includes stroke as well as coronary heart disease (CHD). We investigated whether IGT is a risk factor for stroke. The incidence of stroke and CHD in a cohort population (n = 2938) consisting of participants of the 1990-1997 Funagata study was assessed through interviews with the participants and their family members and reviews of death certificates and residence transfer documents through 2002. Glucose tolerance at the baseline was classified according to the criteria of the 1998 World Health Organization (normal glucose tolerance, n = 2189; IGT, n = 320; and diabetes, n = 286). The cumulative incidences among the groups were compared using the Kaplan-Meier product-limit method, and the risks of these conditions were evaluated by person-year and Cox proportional hazard methods. During the 147-month (mean, 116.5 months) follow-up, 158 (normal glucose tolerance, IGT, and diabetes: 94, 35, and 29, respectively) participants experienced a stroke and 94 (54, 16, and 24, respectively) experienced CHD. By the person-year method, IGT and diabetes were shown to be significant risk factors for stroke and CHD (odds ratio, 1.87 [95% confidence interval, 1.73-2.03] and 3.57 [3.21-3.98] for stroke; 1.53 [1.31-1.78] and 3.47 [2.91-4.14] for CHD, respectively). Cox proportional hazard analysis showed that IGT was a risk factor for stroke (age-, sex-, and hypertension-adjusted hazard ratio: 1.51 [95% confidence interval, 1.02-2.24], P = .039) but not for CHD (1.21 [0.69-2.313], .509). Impaired glucose tolerance is a risk factor for future stroke in a Japanese population.

[QTc interval and traditional risk factors to atherosclerotic disease in patients with type 1 diabetes]

To evaluate the QTc interval and its relation with clinical, laboratorial variables and LDL susceptibility to in vitro oxidation in patients with type 1 DM, we studied 40 diabetics and 33 non diabetics with 24.83 +/- 10.21 and 23.51 +/- 7.28 years old, respectively matched by sex, age and body mass index (BMI). We evaluated metabolic control, A and B apolipoproteins, LDL oxidation coefficient for spectrophotometry and electrocardiogram (ECG). Interval QTc was calculated by the Bazetts formula. There was no difference in QTc between diabetic and non diabetic groups (394.43 +/- 19.98 ms versus 401.31 +/- 17.83 ms; p = 0.2065). Five diabetics showed increased QTc (396.76 +/- 14.63 ms versus 429.75 +/- 1.89 ms; p < 0.001) and lesser A apolipoprotein levels than rest of diabetic group (74.60 +/- 25.42 mg/dL versus 113.64 +/- 29.79 mg/dL; p = 0,011). In pooled sample, there was correlation between QTc and BMI (rho = -0.288; p = 0.045), pot-prandial glycemia (rho = 0.357; p = 0.016) and 3 h oxidation coefficient (OxC3h) (r = -0.293; p = 0.039). In diabetics, there was correlation between QTc and triglycerides (rho = -0.420; p = 0.023) and OxC3h (r = -0.427; p = 0.021). Although there was no difference between QTc of diabetics and the non diabetics subjects studied, there was correlation with risk factors for the atherosclerotic disease. Further studies are necessary to establish the real predictive value of QTc for this type of disease in the patients with type 1 DM.

Nateglinide reduces carotid intima-media thickening in type 2 diabetic patients under good glycemic control

OBJECTIVE

Postprandial hyperglycemia observed in type 2 diabetes mellitus is a risk factor for atherosclerosis. The aim of this study was to investigate the effect of strict glycemic control by nateglinide on common carotid far wall intima-media thickness in type 2 diabetic patients who were already under good glycemic control.

METHODS AND RESULTS

We performed an open labeled randomized prospective trial on 78 drug-naive type 2 diabetic patients whose HbA1c was less than 6.5%. Thirty-eight patients were randomly assigned to receive nateglinide (270 mg/dL) and 40 to control group (no treatment). After 12 months, a significant reduction in HbA1c was observed in the nateglinide group, whereas a significant increase of HbA1c was observed in the untreated group. The carotid intima-media thickness at the end of 1-year follow-up was significantly reduced in the nateglinide group compared with the untreated group (-0.017+/-0.054 mm/year versus 0.024+/-0.066 mm/year, P=0.0064). Whereas nateglinide treatment also reduced triglyceride, highly-sensitive C-reactive protein, and E-selectin, multiple regression analysis identified HbA1c as the only significant independent determinant of the change in carotid intima-media thickness.

CONCLUSION

In type 2 diabetic patients with good glycemic control, further strict glycemic control by nateglinide results in regression of carotid intima-media thickness.

Involvement of oxidative stress in the pathogenesis of diabetes

Pancreatic beta-cell failure is the common characteristic of type 1 and type 2 diabetes. Type 1 diabetes is induced by pancreatic beta-cell destruction, which is mediated by an autoimmune mechanism and consequent inflammatory process. Various inflammatory cytokines and oxidative stress produced by islet-infiltrating immune cells have been proposed to play an important role in mediating the destruction of beta cells. The JNK pathway is also activated by such cytokines and oxidative stress and is involved in beta-cell destruction. Type 2 diabetes is the most prevalent and serious metabolic disease affecting people all over the world. Pancreatic beta-cell dysfunction and insulin resistance are the hallmark of type 2 diabetes. Once hyperglycemia becomes apparent, beta-cell function gradually deteriorates, and insulin resistance is aggravated. This process is called "glucose toxicity." Under such conditions, oxidative stress is provoked, and the JNK pathway is activated, which is likely involved in pancreatic beta-cell dysfunction and insulin resistance. In addition, oxidative stress and activation of the JNK pathway are involved in the progression of atherosclerosis, which is often observed under diabetic conditions. Taken together, it is likely that oxidative stress and subsequent activation of the JNK pathway are involved in the pathogenesis of type 1 and type 2 diabetes.

Association of C-reactive protein with early-stage carotid atherosclerosis in Japanese patients with early-state type 2 diabetes mellitus

The aim of this study was to assess the association between high sensitivity-C-reactive protein (hs-CRP), a sensitive marker of inflammation, and early-stage carotid atherosclerosis, in patients with early-state type 2 diabetes mellitus. The study subjects were 75 patients with type 2 diabetes mellitus without obvious diabetic vascular complications, who were not on any medication, and whose HbA(1c) level was less than 6.5%. We evaluated the mean intima-media thickness (IMT) of the common carotid artery (CCA) by ultrasound B-mode imaging. Then, we investigated various factors associated with CCA-IMT including hs-CRP. Serum hs-CRP levels correlated well with factors strongly associated with insulin resistance such as homeostasis model assessment of insulin resistance (HOMA-IR), fasting insulin level, and body mass index. Serum hs-CRP also correlated with mean CCA-IMT and serum levels of soluble intercellular adhesion molecule-1. Multivariate regression analysis using mean CCA-IMT as the dependent variable identified only age, hs-CRP, and diastolic blood pressure as independent determinants of mean CCA-IMT. While hs-CRP associates with insulin resistance and subclinical atherosclerosis in ealy-state type 2 diabetes, our data suggest that hs-CRP is a useful marker of subclinical atherosclerosis in early-state type 2 diabetes mellitus independent of factors that directly reflect insulin resistance.

Upper gastrointestinal function and glycemic control in diabetes mellitus

Recent evidence has highlighted the impact of glycemic control on the incidence and progression of diabetic micro- and macrovascular complications, and on cardiovascular risk in the non-diabetic population. Postprandial blood glucose concentrations make a major contribution to overall glycemic control, and are determined in part by upper gastrointestinal function. Conversely, poor glycemic control has an acute, reversible effect on gastrointestinal motility. Insights into the mechanisms by which the gut contributes to glycemia have given rise to a number of novel dietary and pharmacological strategies designed to lower postprandial blood glucose concentrations.

Recent Advances of Intervention to Inhibit Progression of Carotid Intima-Media Thickness in Patients With Type 2 Diabetes Mellitus

BACKGROUND AND PURPOSE

Type 2 diabetes is associated with a high cardiovascular morbidity and mortality. Recent advances of intervention studies in type 2 diabetes with use of carotid intima-media thickness (CIMT) measurement as a surrogate end point may allow for better understanding of the undetermined process of atherosclerosis, the effect of interventions, and the usefulness of CIMT to inhibit events of cardiovascular disease.

SUMMARY OF REVIEW

Data were available from 11 studies (n=1578) in subjects with type 2 diabetes (including impaired glucose tolerance, n=132) that evaluated the effect of interventions on change in CIMT. The overall weighed rate of change in mean CIMT based on data among control groups (ie, type 2 diabetes without interventions) was 0.034 mm/y (95% CI, 0.029 to 0.039; median SD, 0.054), in which mean HbA(1c) was 7.86% (95% CI, 7.72 to 8.00; median SD, 1.5). A significant close correlation of HbA(1c) with rate of CIMT change was found (R(2)=0.35, P=0.01). Agents for lowering of blood glucose, platelet activation, or blood pressure significantly reduced the CIMT increase, independent of blood glucose control. This implies that other mechanisms of such agents to diminish CIMT increase should be explored.

CONCLUSIONS

CIMT measurement may contribute to elucidating the short- and/or long-term effect of interventions on the rate of change in CIMT in relation to the levels of various risk factors. Although the method needs further standardization, pharmacological interventions are likely to inhibit progression of CIMT, leading to a reduction of cardiovascular events.

Effect of peroxisome proliferator-activated receptor gamma agonist treatment on subclinical atherosclerosis in patients with insulin-requiring type 2 diabetes

OBJECTIVE

To determine the effect of thiazolidinedione treatment on subclinical atherosclerosis progression in insulin-requiring patients with clinical characteristics suggesting type 2 diabetes.

RESEARCH DESIGN AND METHODS

Eligible participants (n = 299) were randomized within strata of baseline common carotid artery (CCA) intima-media thickness (IMT) (<0.8 mm, >or=0.8 mm) to 400 mg troglitazone daily or placebo for 2 years. A general linear mixed-effects model was used to compare the rate of change in CCA-IMT between treatment groups.

RESULTS

Overall, average rates of CCA-IMT change were not significantly different between troglitazone- and placebo-treated subjects (0.0030 +/- 0.021 vs. 0.0066 +/- 0.021 mm/year; P = 0.17). In the stratum of subjects with CCA-IMT >or=0.8 mm, troglitazone significantly reduced the progression of CCA-IMT relative to placebo (0.0013 +/- 0.022 vs. 0.0084 +/- 0.023 mm/year; P = 0.03). Fasting glucose, insulin, and HbA(1c) were significantly lower in troglitazone- versus placebo-treated subjects (P < 0.01). Whereas blood pressure significantly differed between treatment groups in the >or=0.8-mm stratum, there was no difference between treatment groups in the <0.8-mm stratum.

CONCLUSIONS

Insulin sensitization and reduction in blood pressure may be contributory mechanisms by which troglitazone reduced subclinical atherosclerosis progression in this cohort of well-controlled insulin-dependent patients with clinical characteristics suggesting type 2 diabetes.

Increased pulse-wave velocity in patients with anxiety: implications for autonomic dysfunction

Decreased vagal function is associated with vascular dysfunction. In this study, we compared vascular indices and correlated heart rate and QT variability measures with vascular indices in patients with anxiety disorders and normal controls. We compared age- and sex-matched controls (n=23) and patients with anxiety (n=25) using the Vascular Profiler (VP-1000; Colin Medical Instruments, Japan), approved by the US Food and Drug Administration. Using this machine, we obtained ankle and brachial blood pressure (BP) in both arms (brachial), both legs (ankle), and carotid artery, and lead I electrocardiogram (ECG) and phonocardiogram. Using these signals, pulse-wave velocity (PWV), and arterial stiffness index % and preejection period can be calculated. We also obtained ECG sampled at 1000 Hz in lead II configuration in supine posture to obtain beat-to-beat interbeat interval (R-R) and QT interval variability for 256 s. Patients with anxiety had significantly higher carotid mean arterial pressure (MAP) %, brachial-ankle PWV (BAPWV), arterial stiffness index %, MAP, and diastolic BP of the extremities compared to controls. We found significant negative correlations (r values from .4 to .65; P<.05 to .007) between R-R interval high-frequency (0.15-0.5 Hz) power (which is an indicator of cardiac vagal function), and increased BAPWV and systolic BP of the extremities only in patients. We were unable to find such correlations in controls. We also found significant positive correlations between QT variability index (a probable indicator of cardiac sympathetic function) and MAP of the extremities and BAPWV only in the patient group. These findings suggest an important association between decreased vagal and increased sympathetic function, and decreased arterial compliance and possible atherosclerotic changes and increased BP in patients with anxiety.

Strict glycemic control ameliorates the increase of carotid IMT in patients with type 2 diabetes

The aim of this study was to investigate the effect of strict glycemic control on the carotid artery intima-media thickness (IMT) in type 2 diabetic patients who initially had good glycemic control (HbA1c between 5.8 and 6.4 %). The subjects were 67 patients showing deterioration of the mean HbA1c over 3 years by more than 0.2% from baseline (D group) and 33 subjects showing improvement of the mean HbA1c by more than 0.2% from baseline (A group). The clinical characteristics and annual change of IMT during the observation period were compared between the two groups in a 3-year retrospective longitudinal study. The baseline characteristics and the mean values of BMI, blood pressure, and serum lipids during the study period did not differ significantly between the two groups. However, the mean HbA1c of A group was significantly lower than that of D group (5.67 +/- 0.10 vs. 6.28 +/- 0.08, mean +/- SE, p<0.001). The adjusted annual increase rate of IMT was significantly less in A group than in D group (-0.035 +/- 0.019 vs. 0.036 +/- 0.015 mm, M +/- SEM, p<0.001). These results indicate that further improvement of glycemic control from a good HbA1c value can prevent an increase of IMT in type 2 diabetic patients.

Association of postprandial hyperglycemia with in vitro LDL oxidation in non-smoking patients with type 1 diabetes--a cross-sectional study

BACKGROUND

Cardiovascular disease is the main cause of death in patients with type 1 diabetes. Since oxidized low density lipoprotein (LDL) is considered to be a critical factor in the atherosclerotic process, the aim of our study was to assess the influence of different parameters of glycemic control on susceptibility to oxidative stress from low density lipoprotein (LDL) in patients with type 1 diabetes without microvascular or macrovascular complications.

METHODS

Forty patients and 33 non-diabetic individuals matched for gender, age and body mass index (BMI) were evaluated. The two groups underwent determination of lipid profile, fasting and postprandial glucose control and measurement of glycated hemoglobin (HbA1c). Spectrophotometric analysis of the LDL oxidation index was performed before and 1, 3, 6 and 24 h after the addition of copper sulfate to purified LDL fractions.

RESULTS

The oxidation coefficient for LDL presented similar basal values in the two groups; however, at 3 h, LDL showed a higher degree of oxidation in patients with type 1 diabetes. Correlations with the metabolic control variables were significant only for postprandial glycemia. Stepwise multiple regression showed that post-prandial glycemia and sex were the significant independent variables.

CONCLUSION

LDL from patients with type 1 diabetes showed high susceptibility to oxidative stress and this susceptibility was markedly related to the postprandial glucose levels. The influence of our findings on the development of chronic complications in patients with type 1 diabetes must be addressed in prospective studies.

Small low-density lipoprotein and small low-density lipoprotein/total low-density lipoprotein are closely associated with intima-media thickness of the carotid artery in Type 2 diabetic patients

BACKGROUND

The intima-media thickness (IMT) of the carotid artery, as determined by ultrasonography, is useful for reflecting the extent of subclinical atherosclerosis. We investigated the relationship between IMT and the serum concentrations of small low-density lipoprotein (LDL) in diabetic patients.

METHODS

The study was conducted with 27 Type 2 diabetic patients (14 males and 13 females; mean age=62.6+/-8.3 years) and 12 age-matched healthy controls. The LDL subfraction was measured using a polyacrylamide gel electrophoresis method. Vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) concentrations were measured by an enzyme immunoassay. The IMT was expressed as the maximum IMT (Max-IMT) and average IMT (Ave-IMT) of the carotid artery, measured by ultrasonography.

RESULTS

Both the IMT and the small LDL concentrations were significantly increased in the diabetic patients compared with the healthy participants. The IMTs were significantly correlated with small LDL concentration and small LDL/total LDL more than LDL concentrations by multivariate analysis. The IMTs were not significantly correlated with the serum VEGF or PDGF concentrations. The patients with a larger IMT had a significantly higher prevalence of hypertension or ischemic heart disease than did the patients with a normal IMT.

CONCLUSIONS

The increased small LDL concentrations and small LDL/total LDL, in addition to total LDL concentrations, in Type 2 diabetic patients are closely associated with increased IMT of the carotid artery.

The relationship between age and carotid artery intima-media thickness, hemoglobin A1c in nondiabetic, healthy geriatric population

The aim of the study was to investigate a casual relationship between age and carotid artery intima-media thickness (IMT) and hemoglobin A1c (HbA1c) levels and to assess the effects of possible risk factors in healthy nondiabetic elderly. Seventy-two healthy, well-educated, nondiabetic, healthy elderlies (mean age: 71.5+/-5.01 years; 43 male, 29 female) were enrolled in the study. Comprehensive assessments including a battery of psychosocial and functional performance tests were performed to all subjects. All of them were also asked about health prevention topics including exercise, dietary habits, smoking, vaccination, cholesterol screening, etc. Carotid artery IMT was measured by ultrasound. Blood samples were obtained for fasting glucose, HbA1c, cholesterol, triglyceride and fibrinogen. The mean carotid artery IMT was 0.94+/-0.13 mm and the mean HbA1c level was 5.29+/-0.65 mg/dl. There was no significant correlation between age and carotid artery IMT (r(s)=0.15), HbA1c levels (r(s)=-0.08) and other possible atherosclerosis risk factors. Also there was no correlation between carotid artery IMT and HbA1c levels (r(s)=0.14). Our data indicated that the carotid artery IMT, HbA1c and age are not associated in a geriatric healthy, well-educated population. Comparative studies done on the elderly who do not benefit from preventive health care programs are needed to establish if preventive health care measures and risk factor modification are important in the elderly age group.

Relationship between HbA1c level and peripheral arterial disease

OBJECTIVE

Homeostatic glucose control may play an important role in the development of peripheral arterial disease among individuals without diabetes. We sought to evaluate the association of HbA(1c) (A1C) with peripheral arterial disease in a representative sample of the U.S. population with and without diabetes.

RESEARCH DESIGN AND METHODS

A cross-sectional study was conducted among 4,526 National Health and Nutrition Examination Survey 1999-2002 participants > or = 40 years of age. Peripheral arterial disease was defined as an ankle-brachial index <0.9 (n = 327).

RESULTS

Among nondiabetic subjects, the age-standardized prevalence of peripheral arterial disease was 3.1, 4.8, 4.7, and 6.4% for participants with an A1C <5.3, 5.3-5.4, 5.5-5.6, and 5.7-6.0%, respectively (P trend <0.001). The prevalence of peripheral arterial disease was 7.5 and 8.8% for diabetic participants with A1C <7 and > or = 7%, respectively. After multivariable adjustment and compared with nondiabetic participants with A1C <5.3%, the odds ratio (95% CI) of peripheral arterial disease for nondiabetic participants with an A1C of 5.3-5.4, 5.5-5.6, and 5.7-6.0% was 1.41 (0.85-2.32), 1.39 (0.70-2.75), and 1.57 (1.02-2.47), respectively, and it was 2.33 (1.15-4.70) and 2.74 (1.25-6.02) for diabetic participants with A1C <7 and > or = 7%, respectively.

CONCLUSIONS

An association exists between higher levels of A1C and peripheral arterial disease, even among patients without diabetes. Individuals with A1C levels > or = 5.3% should be targeted for aggressive risk factor reduction, which may reduce the burden of subclinical cardiovascular disease even among those without diabetes.

Increased augmentation of central blood pressure is associated with increases in carotid intima-media thickness in type 2 diabetic patients

AIMS/HYPOTHESIS

Type 2 diabetes is associated with a two- to seven-fold increase in cardiovascular morbidity and mortality. The aim of this study was to determine the relationships between intima-media thickness (IMT), an established marker of atherosclerosis, large artery function and other determinants of cardiovascular risk in type 2 diabetic patients.

METHODS

We studied 228 type 2 diabetic patients (75 women, aged 62+/-2 years [mean+/-SEM]). Carotid IMT was bilaterally measured using ultrasound technology. Applanation tonometry and pulse wave analysis were used to measure aortic systolic and diastolic blood pressures, central pressure augmentation (AG) and the augmentation index (AIx), a measure of systemic arterial stiffness. Conventional cardiovascular risk factors (lipids, HbA(1)c, smoking and diabetes duration) were also assessed.

RESULTS

Women had higher AG and AIx (p<0.0001), despite comparable systolic BP and heart rate in women and men. In women, AG (r=0.39, p<0.001), age (r=0.32, p<0.01), brachial systolic BP (r=0.34, p<0.01) and aortic systolic BP (r=0.34, p<0.01) correlated with IMT. In men, age (r=0.41, p<0.001), diabetes duration (r=0.25, p<0.01), AG (r=0.22, p<0.01), aortic systolic BP (r=0.21, p<0.01), brachial systolic BP (r=0.21, p<0.01) and body weight (r=0.16, p<0.05) correlated with IMT. In multiple linear regression analyses, AG and aortic systolic BP, but not brachial systolic BP, were age-independent determinants of IMT in men and women. In all patients, increased AG (adjusted for sex, age and heart rate) correlated with longer duration of diabetes, urinary albumin excretion and IMT.

CONCLUSIONS/INTERPRETATION

Measures of central systolic pressure correlate with carotid IMT, independently of age and other risk markers.

alpha-Glucosidase inhibitor reduces the progression of carotid intima-media thickness

OBJECTIVE

An open randomized prospective study was performed to elucidate the effect of an alpha-glucosidase inhibitor, voglibose, on the progression of atherosclerosis in subjects with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Voglibose at a dose of 0.4-0.6 mg/day was added on 51 subjects out of 101 type 2 diabetic patients being treated with diet, sulphonylurea (SU) or insulin injections, and the average (AveIMT) and maximum intima-media thickness (MaxIMT) of their carotid arteries were examined for 3 years.

RESULTS

Irrespective of the differences in treatments, addition of voglibose reduced the progression of AveIMT and MaxIMT to -0.024 +/- 0.047 (+/-S.D.) and -0.021 +/- 0.144 mm/year, respectively. Without voglibose, diabetic patients showed significant (P < 0.0001) progression of AveIMT and MaxIMT (0.056 +/- 0.046 and 0.098 +/- 0.122 mm/year, respectively). The administration of voglibose resulted in a significant reduction of hemoglobin A1c (HbA1c), total cholesterol and triglyceride concentrations, as well as an increase in HDL cholesterol concentration. Multivariate regression analysis showed that administration of voglibose independently reduced the progression of AveIMT by 0.069 mm/year (P < 0.0001).

CONCLUSIONS

These results suggest that voglibose reduces the progression of IMT and may be a candidate for an anti-atherosclerotic drug for type 2 diabetic patients.

Non-HDL Cholesterol as a Predictor of Carotid Atherosclerosis in the Elderly

The aim of the present study was to evaluate sclerotic lesions of the common carotid artery by ultrasonography in 921 in-patients aged 65 years and older (77 +/- 7 years) and investigate whether lipid levels were associated with carotid atherosclerosis. In men, an increased risk for carotid atherosclerosis was associated with increased levels of low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C). Compared to men with the lowest tertile of LDL-C levels (< 83.4 mg/dl), the adjusted odds ratio was 2.502 (95% confidence interval: 1.426-4.390) in those with the middle tertile (83.4-115.2 mg/dl), and 2.688 (1.509-4.790) in those with the highest tertile ( > 115.2 mg/dl). Like the LDL-C level, the non-HDL-C level showed a positive and linear relationship with carotid atherosclerosis. Compared to men with the lowest tertile of non-HDL-C levels ( < 101 mg/dl), the adjusted odds ratio was 2.881 (1.633-5.081) for those with the middle tertile (101-135 mg/dl), and 2.990 (1.651-5.415) for those with the highest tertile ( > 135 mg/dl). Similarly, in women, an increased risk for carotid atherosclerosis was also positively and linearly associated with LDL-C and non-HDL-C. The Non-HDL-C level is a potential predictor of risk for carotid atherosclerosis in the elderly.

Effect of cilostazol, a phosphodiesterase inhibitor, on carotid IMT in Japanese type 2 diabetic patients

The aim of this study was to investigate the effect of cilostazol, a cAMP phosphodiesterase inhibitor, on carotid artery intima-media thickness (IMT) and on the incidence of cardiovascular events in Japanese subjects with type 2 diabetes. A total of 62 type 2 diabetic subjects were allocated equally to the cilostazol treatment group (n = 31) and the control group (n = 31). Carotid IMT was evaluated before and after treatment using B-mode ultrasonography. After the study period (mean +/- SD: 2.6 +/- 0.17 years), carotid IMT showed a significantly greater increase in the control group than in the cilostazol group (0.12 +/- 0.14 mm vs. 0.04 +/- 0.02 mm, p < 0.05). In the control group, 1 out of 31 patients suffered from symptomatic cerebral infarction and 1 had angina pectoris during the observation period. On the other hand, no subject in the cilostazol group developed cardiovascular events during the study period. At baseline, the diabetic patients given cilostazol had a significantly lower HbA1c level than the control subjects, but the other atherosclerotic risk factors (BMI, blood pressure, and serum lipids) and the duration of diabetes did not differ between the two groups. These results indicate that cilostazol therapy can attenuate the increase of carotid artery IMT in Japanese subjects with type 2 diabetes.

Metformin attenuates progression of carotid arterial wall thickness in patients with type 2 diabetes

To investigate the anti-atherogenic effect of metformin, we prospectively evaluated the effect of metformin treatment on common carotid intima-media thickness (CCA-IMT) in patients with type 2 diabetes. A 2-year open prospective study was performed. Thirty-six patients were treated with metformin (500-750 mg per day). CCA-IMT was measured after 1- and 2-year treatment. Changes in CCA-IMT were compared with control patients. After 2-year metformin therapy, the progression of CCA-IMT was significantly less than 56 control patients (0.02+/-0.08 mm versus 0.07+/-0.08 mm, P<0.01). Metformin therapy did not alter body weight, blood pressure, HbA1c, and serum lipids relative to the control. Thus, metformin attenuates the progression of CCA-IMT. This anti-atherogenic effect is not mediated through changes in classical cardiovascular risk factors.

Effects of sex, age and BMI on screening tests for impaired glucose tolerance

The discriminating abilities of fasting plasma glucose (FPG) and HbA1c were compared on screening tests for impaired glucose tolerance (IGT) and IGT plus diabetes mellitus by the receiver operating characteristic (ROC) curve analysis. Furthermore, effects of sex, age and BMI were examined on sensitivity and specificity of the optimal cutoff points. This study included 997 subjects who were recruited for 75 g OGTT after the first screening of the Japan Diabetes Prevention Program. According to the 1997 criteria of the American Diabetes Association (ADA), 140 subjects were classified as diabetic and 256 as IGT. The areas under the ROC curves of FPG were significantly larger than those of HbA1c. The optimal cutoff points of FPG were 102 mg/dl for IGT and 105 mg/dl for IGT plus diabetes mellitus. Those of HbA1c were both 5.3%. In screening with FPG, females had significantly lower sensitivity and higher specificity than males, and the specificity for IGT plus diabetes mellitus was the lowest in the obese group. In screening with HbA1c, the specificity was low in the older and the obese groups. We concluded that FPG was superior to HbA1c for screening of IGT and IGT plus diabetes mellitus and the optimal cutoff point of FPG would be 102 mg/dl or greater.

Risk factors for asymptomatic atherosclerosis in Japanese type 2 diabetic patients without diabetic microvascular complications

Atherosclerotic vascular diseases are frequently associated with diabetes mellitus. There has been increasing evidence showing that the atherosclerotic diseases in diabetic patients are distinct from diabetic microvascular complications as to their pathophysiology and epidemiology. However, we have no information on the prevalence of asymptomatic atherosclerosis in diabetic patients before the onset of microvascular diseases. In the present investigation, we aimed to evaluate risk factors for the atherosclerosis in type 2 diabetic patients without the microvascular diseases. For this purpose, we evaluated atherosclerotic change of carotid arteries in 125 Japanese type 2 diabetic patients who had neither atherosclerotic vascular diseases nor diabetic microvascular complications. When atherosclerotic change was defined as the mean intima-media thickness (IMT) of >/= 1.1 mm and/or the presence of plaque lesion, 50% of patients had atherosclerosis of the carotid arteries. Risk factors for the carotid atherosclerosis were age, low-density lipoprotein (LDL)-cholesterol, hypertension, and diabetes treatment. Age and LDL-cholesterol were associated with mean IMT. Age, diabetes treatment, LDL-cholesterol, and hypertension were positively associated with plaque lesion, while high-density lipoprotein (HDL)-cholesterol was negatively associated with it. Fasting plasma glucose, glycosylated hemoglobin (HbA(1c)), and known diabetes duration remained unassociated with any parameters of asymptomatic atherosclerosis of the carotid arteries. These results indicate that glycemic control is unrelated with asymptomatic atherosclerosis in type 2 diabetic patients without diabetic microvascular complications. Conventional risk factors and diabetes treatment are independently associated with atherosclerosis of the carotid arteries in these patients.

Relationship between hyperinsulinemia and pulse wave velocity in moderately hyperglycemic patients

AIM

Arterial stiffness assessed by pulse wave velocity (PWV) reflects early stage arteriosclerosis. The influence of hyperinsulinemia on peripheral vascular disease (PVD) is still unknown. We determined the influences of hyperinsulinemia on PVD assessed by PWV in moderately hyperglycemic patients.

METHODS

Thirty-six moderately hyperglycemic, outcoming patients were recruited in this study. All subjects were divided into two groups by fasting immunoreactive insulin (F-IRI) concentrations; group A; F-IRI> or =5 microU/ml, group B; F-IRI<5 microU/ml. Both hbPWV (from heart to brachial artery) and baPWV (brachial to artery to ankle) were evaluated by using Form PWV/ABI, in addition to ankle-brachial pressure index (ABPI).

RESULTS

In group A, both hbPWV and baPWV showed significantly higher values than in group B. ABPIs were not different between two groups. Although age, FPG, plasma HbA1c, serum total-cholesterol, HDL-cholesterol concentrations, and systolic and diastolic blood pressure were at same levels in group A as group B, body mass index, HOMA-R, serum triglyceride concentrations were significantly higher in group A, indicating the existence of insulin resistance in group A.

CONCLUSION

Hyperinsulinemia may be involved in the development of PVD in moderately hyperglycemic patients.

Prevalence and major risk factors of reduced flow volume in lower extremities with normal ankle-brachial index in Japanese patients with type 2 diabetes

OBJECTIVE

To clarify the prevalence and major risk factors of reduced flow volume in lower extremities with normal ankle-brachial index (ABI) in Japanese patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We recruited 208 consecutive type 2 diabetic patients and 33 age-matched nondiabetic subjects (control group) admitted to our hospital. Thirty-two of the patients had low ABI (<0.90) and intermittent claudication (peripheral arterial disease [PAD] group), and 176 patients had normal ABI (>0.9) (non-PAD group). We evaluated flow volume and resistive index, as an index of arterial resistance to blood flow, at the popliteal artery using gated two-dimensional cine-mode phase-contrast magnetic resonance imaging.

RESULTS

Simple linear regression analysis showed a negative correlation between resistive index and total flow volume in the non-PAD group (r = -0.714, P < 0.001). We defined the means +/- 2 SD of these parameters in the control group as the normal range; abnormal resistive index was >1.017, and abnormal flow volume was <50.8 ml/min. The non-PAD group was divided according to the levels of these parameters: 80 patients had both normal resistive index and normal flow volume (normal group); of 96 patients with higher resistive index, 63 had normal flow volume (borderline group) and 33 had reduced flow volume (reduced group). Multiple regression analysis demonstrated that the major risk factors for reduced flow volume were age, hypertension, and diabetic nephropathy (r(2) = 0.303, P < 0.001).

CONCLUSIONS

The prevalence of patients without PAD with reduced flow volume in the lower extremities was 16% (n = 33) and comparable with that of patients with PAD with intermittent claudication (n = 32), suggesting that increase in arterial resistance to blood flow may be one of the major causes of lower extremity arterial disease in Japan.

Diabetes and progression of carotid atherosclerosis: the insulin resistance atherosclerosis study

OBJECTIVE

We sought to determine the rate of progression of carotid atherosclerosis in persons with normal glucose tolerance, impaired glucose tolerance, and undiagnosed and diagnosed type 2 diabetes.

METHODS AND RESULTS

The Insulin Resistance Atherosclerosis Study (IRAS) is an observational cohort study in which 1192 men and women were examined at a 5-year interval. Participants of 3 ethnic groups (non-Hispanic white, African American, and Hispanic) were selected from the general population to represent a range of glucose tolerance. Baseline and follow-up ultrasound studies were obtained to estimate progression of common carotid artery (CCA) and internal carotid artery (ICA) intimal-medial thickness (IMT). Baseline glucose tolerance status was defined by an oral glucose tolerance test and World Health Organization criteria. In persons with normal glucose tolerance, progression of CCA IMT was 3.8 microm/y, and ICA IMT, 17.7 microm/y. In both CCA and ICA, progression of IMT, unadjusted for cardiovascular disease (CVD) risk factors, was approximately twice the rate in persons with diabetes than in those with normal or impaired glucose tolerance. Adjustment for CVD risk factors attenuated these differences somewhat in both sites of the carotid artery. Persons with undiagnosed diabetes had a greater ICA IMT progression rate than did persons with diagnosed diabetes (33.9 microm/y vs 26.6 microm/y, P=NS). Progression rates did not differ between persons with normal and impaired glucose tolerance.

CONCLUSIONS

Progression of carotid atherosclerosis is accelerated in persons with diabetes. Progression of ICA IMT is most pronounced in persons with undiagnosed diabetes. Early identification of diabetes and CVD risk factor control might reduce its atherosclerotic complications.