Is the carotid intima-media thickness really a good surrogate marker of atherosclerosis?

Serum anti‑KIAA0513 antibody as a common biomarker for mortal atherosclerotic and cancerous diseases

Numerous antibody biomarkers have been reported for cancer and atherosclerosis-related diseases. The major complications of atherosclerosis and diabetes mellitus (DM) are acute ischemic stroke (AIS), cardiovascular disease (CVD) and chronic kidney disease (CKD). Cancer development is accompanied by arterial disorders, such as angiogenesis and atherosclerosis, and DM is a risk factor for the development of certain types of cancer. Atherosclerosis-related diseases and cancers are therefore interrelated and could be detected using a common biomarker. In the present study, the initial screening using the protein array method identified KIAA0513 as an antigen recognized by serum IgG antibodies in patients with atherosclerosis. The amplified luminescent proximity homogeneous assay-linked immunosorbent assay revealed significantly higher serum antibody levels against recombinant KIAA0513 protein in patients with AIS, transient ischemic attack (TIA), DM, CVD, obstructive sleep apnea syndrome (OSAS), CKD and solid cancers, such as esophageal, gastric, colon, lung and breast cancers, compared with healthy donors. A receiver operating characteristic (ROC) analysis revealed that the highest areas under the ROC curves of anti-KIAA0513 antibodies were obtained for esophageal cancer, nephrosclerosis-type CKD and DM. Spearman's correlation analysis revealed that serum anti-KIAA0513 antibody levels were associated with maximum intima-media thickness and plaque score, which are indices of atherosclerosis and stenosis. Serum anti-KIAA0513 antibody markers appear to be useful for diagnosing AIS, TIA, DM, CVD, OSAS, CKD and solid cancers, and may reflect common arterial alterations leading to atherosclerotic and cancerous diseases.

Utility of atherosclerosis-associated serum antibodies against colony-stimulating factor 2 in predicting the onset of acute ischemic stroke and prognosis of colorectal cancer

Introduction

Autoantibodies against inflammatory cytokines may be used for the prevention of atherosclerosis. Preclinical studies consider colony-stimulating factor 2 (CSF2) as an essential cytokine with a causal relationship to atherosclerosis and cancer. We examined the serum anti-CSF2 antibody levels in patients with atherosclerosis or solid cancer.

Methods

We measured the serum anti-CSF2 antibody levels via amplified luminescent proximity homogeneous assay-linked immunosorbent assay based on the recognition of recombinant glutathione S-transferase-fused CSF2 protein or a CSF2-derived peptide as the antigen.

Results

The serum anti-CSF2 antibody (s-CSF2-Ab) levels were significantly higher in patients with acute ischemic stroke (AIS), acute myocardial infarction (AMI), diabetes mellitus (DM), and chronic kidney disease (CKD) compared with healthy donors (HDs). In addition, the s-CSF2-Ab levels were associated with intima-media thickness and hypertension. The analyzes of samples obtained from a Japan Public Health Center-based prospective study suggested the utility of s-CSF2-Ab as a risk factor for AIS. Furthermore, the s-CSF2-Ab levels were higher in patients with esophageal, colorectal, gastric, and lung cancer than in HDs but not in those with mammary cancer. In addition, the s-CSF2-Ab levels were associated with unfavorable postoperative prognosis in colorectal cancer (CRC). In CRC, the s-CSF2-Ab levels were more closely associated with poor prognosis in patients with p53-Ab-negative CRC despite the lack of significant association of the anti-p53 antibody (p53-Ab) levels with the overall survival.

Conclusion

S-CSF2-Ab was useful for the diagnosis of atherosclerosis-related AIS, AMI, DM, and CKD and could discriminate poor prognosis, especially in p53-Ab-negative CRC.

Association of Fish and Omega-3 Fatty Acid Intake with Carotid Intima-Media Thickness in Middle-Aged to Elderly Japanese Men and Women: The Toon Health Study

Fish and omega-3 fatty acid consumption is known to be beneficial for cardiometabolic health. However, the related evidence for individuals with a relatively higher intake of fish or omega-3 unsaturated fatty acids, e.g., Japanese individuals, is scarce. Therefore, this study aimed to examine the association of fish and omega-3 fatty acid intakes with the carotid intima-media thickness (C-IMT) in the Japanese population. In total, 1803 Japanese men and women aged 30–84 years without a history of myocardial infarction or angina pectoris were included in the study. The fish and omega-3 fatty acid intakes were estimated using food frequency questionnaires. The C-IMT was measured using ultrasound imaging, and the participants were classified into three groups: normal, moderate (1.1 to 1.4 mm of maximum C-IMT), and severely increased C-IMT (≥1.5 mm). Multinomial logistic regression models were used to calculate the odds ratio (OR) and 95% confidence intervals (95% CI) of the presence of moderately and severely increased C-IMT. The omega-3 fatty acid intake was shown to be associated with lower odds of severely increased C-IMT. The multivariable-adjusted OR (95%CI) was 0.55 (0.31–0.97; p for trend = 0.04). We also found a borderline significant negative association between fish intake and the presence of severely increased C-IMT. In conclusion, omega-3 fatty acid intake might protect against the development of atherosclerosis in the Japanese population.

Serum anti-SERPINE1 antibody as a potential biomarker of acute cerebral infarction

The presence of disease-specific antigens and autoantibodies in the sera of patients with atherosclerosis-related diseases has been widely reported and is considered to result from inflammation of the arterial wall and the involvement of immune factors. The aim of this study was to identify a novel antibody in patients with ischemic stroke by serological identification of antigens using recombinant cDNA expression cloning from patients who had a transient ischemic attack (TIA). We identified the serpin peptidase inhibitor, clade E member 1 (SERPINE1), as a candidate antigen. The serum anti-SERPINE1 antibody levels quantified using amplified luminescent proximity homogeneous assay-linked immunosorbent assay were significantly higher in patients with ischemic stroke, including those with acute cerebral infarction (aCI), TIA, and chronic cerebral infarction, than in healthy donors. The antibody levels were strongly associated with old age, female sex, and presence of hypertension, diabetes mellitus, and cardiovascular disease. Age and intima-media thickness of the carotid artery were positively correlated with antibody levels, which suggests that SERPINE1 may reflect the progression of atherosclerosis. In a multivariate analysis, SERPINE1 antibody level was an independent predictor of aCI. Thus, the serum levels of anti-SERPINE1 antibody could potentially serve as a biomarker of atherothrombotic infarction.

Rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone therapy increases carotid intima-media thickness and plaque score with von Willebrand factor activity elevation in patients with malignant lymphoma

An increased risk for atherosclerosis has been noted in cancer survivors; however, studies that focus on the risk of atherosclerosis in patients treated with chemotherapy are scarce. Therefore, we evaluated 32 patients who received rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP) therapy for B-cell malignant lymphoma by analysing the changes in atherosclerosis. Just before each treatment course, plasma levels of von Willebrand Factor (vWF) activity were evaluated, and carotid ultrasonography was performed at baseline and after the final treatment. Throughout the follow-up period, plasma vWF levels showed significantly transient increased by approximately 20%-40%. Both mean carotid intima-media thickness (IMT) and plaque score (PS) significantly increased during the 36.6 ± 26.0 weeks of observation (mean IMT: 0.724 ± 0.118 to 0.767 ± 0.129 mm; PS: 4.31 ± 3.53 to 4.87 ± 3.88, P < 0.001). Our study suggests that R-CHOP therapy promotes atherosclerosis.

Markers of cardiovascular disease risk in sleep-disordered breathing with or without comorbidities: the Nagahama Study

STUDY OBJECTIVES

Whether the association between sleep-disordered breathing (SDB) and cardiovascular disease (CVD) is independent of comorbid risk factors for CVD is controversial. The objective of this study is to elucidate whether the association between SDB severity and the surrogate markers of CVD evets differs in relation to the number of comorbidities.

METHODS

This cross-sectional study included 7731 participants. Severity of SDB was determined by the oxygen desaturation index adjusted by actigraph-measured objective sleep time. Participants were stratified according to SDB severity and the number of comorbidities (hypertension, diabetes, dyslipidemia and obesity), and the associations between the maximum value of intima-media thickness of the common carotid artery (CCA-IMT-max), brachial-ankle pulse wave velocity (baPWV) and cardio-ankle vascular index (CAVI) were evaluated.

RESULTS

Among participants with no risk factor, CCA-IMT-max increased according to SDB severity (n = 1022, P <0.0001). Even after the matching of background, the median CCA-IMT-max value was 14% higher in moderate-severe SDB cases than those without SDB (n=45 in each group, P=0.020). The difference was not significant for baPWV and CAVI. On the other hand, a significant difference in CCA-IMT-max was not found in those with multiple comorbidities. Consistently, multiple regression analysis revealed an independent association between CCA-IMT-max and moderate-severe SDB for all study participants (β: 0.0222 (95% confidence interval: 0.0039-0.0405), P=0.017), but the association was not significant for stratified participants with multiple comorbidities.

CONCLUSIONS

SDB severity is associated with the CCA-IMT-max level, but the independent association becomes weaker for those with multiple comorbidities.

Serum anti-DIDO1, anti-CPSF2, and anti-FOXJ2 antibodies as predictive risk markers for acute ischemic stroke

BACKGROUND

Acute ischemic stroke (AIS) is a serious cause of mortality and disability. AIS is a serious cause of mortality and disability. Early diagnosis of atherosclerosis, which is the major cause of AIS, allows therapeutic intervention before the onset, leading to prevention of AIS.

METHODS

Serological identification by cDNA expression cDNA libraries and the protein array method were used for the screening of antigens recognized by serum IgG antibodies in patients with atherosclerosis. Recombinant proteins or synthetic peptides derived from candidate antigens were used as antigens to compare serum IgG levels between healthy donors (HDs) and patients with atherosclerosis-related disease using the amplified luminescent proximity homogeneous assay-linked immunosorbent assay.

RESULTS

The first screening using the protein array method identified death-inducer obliterator 1 (DIDO1), forkhead box J2 (FOXJ2), and cleavage and polyadenylation specificity factor (CPSF2) as the target antigens of serum IgG antibodies in patients with AIS. Then, we prepared various antigens including glutathione S-transferase-fused DIDO1 protein as well as peptides of the amino acids 297-311 of DIDO1, 426-440 of FOXJ2, and 607-621 of CPSF2 to examine serum antibody levels. Compared with HDs, a significant increase in antibody levels of the DIDO1 protein and peptide in patients with AIS, transient ischemic attack (TIA), and chronic kidney disease (CKD) but not in those with acute myocardial infarction and diabetes mellitus (DM). Serum anti-FOXJ2 antibody levels were elevated in most patients with atherosclerosis-related diseases, whereas serum anti-CPSF2 antibody levels were associated with AIS, TIA, and DM. Receiver operating characteristic curves showed that serum DIDO1 antibody levels were highly associated with CKD, and correlation analysis revealed that serum anti-FOXJ2 antibody levels were associated with hypertension. A prospective case-control study on ischemic stroke verified that the serum antibody levels of the DIDO1 protein and DIDO1, FOXJ2, and CPSF2 peptides showed significantly higher odds ratios with a risk of AIS in patients with the highest quartile than in those with the lowest quartile, indicating that these antibody markers are useful as risk factors for AIS.

CONCLUSIONS

Serum antibody levels of DIDO1, FOXJ2, and CPSF2 are useful in predicting the onset of atherosclerosis-related AIS caused by kidney failure, hypertension, and DM, respectively.

The Impact of Hypertension and Atrial Fibrillation on Cognitive Decline and Subclinical Atherosclerosis

BACKGROUND

Assessment of cognitive impairment and the presence of subclinical atherosclerosis are very important especially in patients with cardiovascular risk factors.

METHODS

We included 155 hypertensive patients (84 with AF versus 71 without AF) to identify the premature cognitive impairment, the earliest signs of subclinical atherosclerosis and onset of myocardial dysfunction and to evaluate the type of anticoagulation used, the importance of CHA₂DS₂-VASc score (3), age (65 years) in hypertensive patients with AF.

RESULTS

Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment Scale (MoCA), Left Ventricular Ejection Fraction (LVEF) were significantly decreased, and Activities of Daily Living Score (ADL), Geriatric Depression Scale(GDS-15), and intima-media thickness (IMT) were significantly increased in hypertensive patients with AF vs. without AF (p < 0.05). MMSE was significantly decreased, ADL and IMT were significant increased in patients with AF and CHA₂DS₂-VASc>3 and non-vitamin K antagonists oral anticoagulants therapy (NOACs)(p < 0.05). Patients with age >65 with AF had higher rates of cognitive impairment (MMSE significant decrease) and a larger IMT (significant increase) versus patients with AF and age <65 (p < 0.05).

CONCLUSIONS

Cognitive impairment is encountered in hypertensive patients having AF. Our conclusions suggest a direct link between cognitive impairment, depression, hypertension, AF, age, CHA₂DS₂-VASc score, type of anticoagulants used, LVEF, cognitive parameters, and IMT. We acknowledge the importance of identifying and preventing cognitive changes.

Safety of different carotid artery revascularization strategies in the coronary artery bypass graft population: study protocol for a systematic review and network meta-analysis

BACKGROUND

Concomitant significant carotid artery occlusive diseases (CAOD) increase the risk of perioperative stroke and death in patients who undergo coronary artery bypass graft (CABG). Although several surgical strategies can be used in the management of such patients, controversy still surrounds which is the best option for CABG patients with accompanying CAOD.

METHODS

Literature searches will be conducted covering articles published in PubMed, the Cochrane Central Register of Controlled Trials, Web of Science, and Embase between January 1989 and December 2019. Search results will be limited to articles published in English. Six surgical strategies using carotid endarterectomy (CEA) or carotid artery stenting (CAS) with different timings (i.e., before, after, or combined with CABG) will be evaluated. Randomized controlled trials and non-randomized studies comparing these strategies will be included. The quality of studies will be critically appraised using the Cochrane risk-of-bias tool or ROBINS-I tool. Since CEA and CAS have comparable effectiveness for the treatment of significant CAOD, we will integrate direct and indirect evidence using network meta-analysis (NMA) to create hierarchies of the six surgical strategies based on their perioperative safety. The primary outcomes will be the probability of perioperative stroke and the probability of perioperative death. Additionally, we will analyze the probability of perioperative myocardial infarction (MI) as a secondary outcome. Pairwise meta-analyses and Bayesian network meta-analyses will be performed for all related outcome measures. Subgroup analyses, sensitivity analyses, and network meta-regression will be conducted to assess the robustness of the findings.

DISCUSSION

This NMA will summarize the direct and indirect evidence of perioperative safety with the aim of providing a ranking of the various surgical strategies. The results of this meta-analysis will provide useful information on optimal surgical management of CABG patients with concomitant significant CAOD.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42020162611.

Ultrasound Measurement of Carotid Intima-Media Thickness and Plaques in Predicting Coronary Artery Disease

Ultrasound measurement of carotid intima-media thickness (CIMT) and plaque thickness (PT) may be an additional tool for risk stratification of patients with suspected acute coronary syndrome (ACS) in the emergency department (ED). The aim of this study was to evaluate the correlation of CIMT and PT with coronary artery disease (CAD) in risk stratification tests.This prospective observational study was conducted in an academic tertiary care ED. Carotid ultrasound measurements were obtained for emergency patients with suspected ACS. Carotid measurements included PT, mean CIMT and maximum CIMT. The correlations between carotid ultrasound and the results of coronary catheter angiography (CA), coronary computed tomography angiography (CCTA) and stress tests were identified. The convenience sample included 58 patients comprising 39 men and 19 women with a mean age of 60 ± 12 y. Twenty-two percent (13/58) of patients were positive for CAD, as indicated by results of the cardiac risk stratification tests. Presence of plaque correlated with CCTA findings, with a high specificity (92.8%) for a positive test. Max CIMT predicted abnormal CCTA (area under the curve [AUC] = 0.93, 95% confidence interval: 0.80-1). The correlations with stress test (0.78, 0.46-1) and CA (0.55, 0.28-0.82) were weaker. Presence of carotid plaque correlated significantly with findings of CAD on all risk stratification tests, but especially with CCTA. Carotid ultrasound could have a role in risk stratification in the ED, though more research is needed.

Improvement of Endothelial Dysfunction of Berberine in Atherosclerotic Mice and Mechanism Exploring through TMT-Based Proteomics

Atherosclerosis is a multifactorial vascular disease triggered by disordered lipid metabolism, characterized by chronic inflammatory injury, and initiated by endothelial dysfunction. Berberine is the main active alkaloid of the herbal medicine Coptidis Rhizoma (Huanglian). Notably, berberine has been shown to have beneficial effects against atherosclerosis. However, the mechanisms of berberine in preventing atherosclerosis are still unclear. This study is aimed at investigating the effects and mechanisms of berberine in protecting the aorta and ameliorating atherosclerosis in apolipoprotein E-deficient (ApoE^−/−) mice. Here, we demonstrated that berberine reduced serum lipid levels, antagonized hepatic lipid accumulation, improved intima-media thickening, and alleviated atherosclerotic lesions in ApoE^−/− mice fed a western-type diet for 12 weeks. Meanwhile, berberine reduced aortic reactive oxygen species (ROS) generation and reduced the serum levels of malondialdehyde (MDA), oxidized low-density lipoprotein (ox-LDL), and interleukin-6 (IL-6). In aortic ring assay, berberine restored aortic endothelium-dependent vasodilatation in vivo and in vitro. Furthermore, 4,956 proteins were identified by proteomic analysis, and 199 differentially expressed proteins regulated by berberine were found to be involved in many biological pathways, such as mitochondrial dysfunction, fatty acid β-oxidation I, and FXR/RXR activation. Summarily, these data suggested that berberine ameliorates endothelial dysfunction and protects against atherosclerosis, and thus may be a promising therapeutic candidate for atherosclerosis.

Impact of Intima-Media Thickness Progression in the Common Carotid Arteries on the Risk of Incident Cardiovascular Disease in the Suita Study

Background

No prospective study of the relationship between intima–media thickness (IMT) progression and incident cardiovascular disease (CVD) has been performed.

Methods and Results

We studied 4724 participants (mean age: 59.7±11.9 years; without CVD at the baseline) who had carotid ultrasonographic measurement of IMT on both sides of the entire carotid artery area (ie, the entire scanned common carotid artery [CCA], carotid artery bulb, internal carotid artery, and external carotid artery areas for both sides) between April 1994 and August 2001. Carotid ultrasonographic follow‐up was performed every 2 years between April 1994 and March 2005 in 2722 of these participants, newly revealing 193 CCA plaques (maximum IMT in the CCA >1.1 mm). We followed up for incident CVD until December 2013. Statistical analyses were performed using a Cox proportional hazards regression model, evaluated using C statistics, and net reclassification improvement. During the 59 909 person‐years of follow‐up, we observed 221 strokes and 154 coronary heart disease events. CCA plaque and maximum IMT in the whole carotid artery area >1.7 mm were risk factors for CVD. CCA plaque presented an increased risk of CVD based on C statistics and the reclassification improvement of the current risk prediction model. After adding the new incident CCA plaques, during the 23 702 person‐years of follow‐up, 69 strokes and 43 coronary heart disease events occurred. The adjusted hazard ratios for incident CCA plaque were 1.95 (95% confidence interval, 1.14–3.30) in CVD and 2.01 (95% confidence interval, 1.01–3.99) in stroke.

Conclusions

Maximum IMT in the CCA contributed significantly but modestly to the predictive power of incident CVD used in calculating traditional risk factors. This study provides the first demonstration that new progression of incident CCA plaque is a CVD risk.

Do traditional cardiovascular risk factors solely explain intima-media thickening in youth with type 1 diabetes?

AIMS

The aim of this study was to assess age-specific carotid intima-media thickness (cIMT) in children and adolescents with type 1 diabetes and to investigate associations between cIMT, age, classical cardiovascular disease (CVD) and other risk factors.

METHODS

This study included a cross-sectional analysis of cIMT in 178 patients with type 1 diabetes and 208 healthy controls across age categories. In patients, the impact of gender, socio-economic status, ethnicity, current and historical body mass index, blood pressure, hemoglobin A1c, high-density lipoprotein, and low-density lipoprotein cholesterol on cIMT was studied in a retrospective follow-up cohort study.

RESULTS

Median cIMT was equally greater in patients versus controls across all age categories (P≤0.03). Regression models in patients confirmed a lack of association between cIMT and classical CVD risk factors.

CONCLUSIONS

Children and adolescents with type 1 diabetes showed greater cIMT than controls in all age categories. Increased cIMT did not seem to be consistently associated with classical adult CVD risk factors, adding to the current debate in pediatrics about the impact on classical CVD risk factors to the development of subclinical atherosclerosis in type 1 diabetes. Future studies are warranted to determine if cIMT could assist in predicting macrovascular complications of type 1 diabetes.

A non-contact approach for PWV detection: application in a clinical setting

A need for screening methods for arteriosclerosis led to the development of several approaches to measure pulse wave velocity (PWV) being indicative of arterial stiffness. Carotid-femoral PWV (cfPWV) can be measured between common carotid artery (CCA) and femoral artery (FA) displaying the physiologically important stiffness of the conduit arteries. However, this measurement approach has several disadvantages, and a local PWV-measurement of CCA-stiffness has been proposed as an alternative in the past. In the presented pilot study, laser Doppler vibrometry (LDV) is used to measure PWV locally in the CCA (PWVLDV) in 48 patients aged between 48 and 70, with known atherosclerotic arterial disease: stabilized coronary artery disease (CAD), cerebro-vascular disease (CVD) or peripheral artery disease (PAD). Additionally, cfPWV, CCA distensibility coefficient (DC), CCA intima-media thickness (IMT), blood pressure (BP) and age were evaluated. LDV is a valid method for local PWV-measurement. The method is potentially easy to use, and causes no discomfort to the patient. PWVLDV correlates with age (R  =  0.432; p  =  0.002) as reported in related studies using other techniques, and measured values lay between 2.5 and 5.8 m s(-1), which is well in line with literature measures of local PWV in the CCA. In conclusion, PWVLDV potentially is a marker for arterial health, but more research in a larger and more homogeneous patient population is mandatory. In future studies, blood velocity measurements should be incorporated, as well as a reference method such as pulse wave imaging (PWI) or magnetic resonance imaging (MRI).

Can carotenoids attenuate vascular aging?

One of the main manifestations of vascular aging is the development of atherosclerotic lesions. These lesions become unstable and prone to rupture due to the formation of reactive oxygen species (ROS) that are produced by the inflammatory milieu in the atherosclerotic plaque. The carotenoids are a group of red, orange, or yellow pigmented polyisoprenoid hydrocarbons synthesized by prokaryotes and higher plants. Lycopene, lutein, and other carotenoids have anti-oxidant activity that attenuates the inflammatory atherosclerotic process and delays vascular aging. This ability improves endothelial function due to the increase in bioavailability of NO. Carotenoid consumption also improves the metabolic profile, decreasing the incidence of diabetes, lowering LDL levels, and improving blood pressure control. The beneficial metabolic effect is translated to improvement in atherosclerosis, which is characterized by a decrease in carotid intima-media thickness. The favorable anti-atherosclerotic effect of carotenoids was also demonstrated in cross-sectional population studies showing a positive correlation between low carotenoid levels and adverse cardiovascular outcome. However, carotenoid utilization failed to decrease major cardiovascular and cerebrovascular events in randomized control double blind trials. The main still unanswered question is: What is the therapeutic role of carotenoids in atherosclerotic disease? Is their anti-atherosclerotic effect restricted to primary prevention or can it alter the prognosis of existing cardiovascular and cerebrovascular diseases?

Arterial wall elasticity measured using the phased tracking method and atherosclerotic risk factors in patients with type 2 diabetes

AIM

The aim of this study was to investigate the relationship between atherosclerotic manifestations and brachial and radial arterial wall elasticity (AWE) measured using the phased tracking method in patients with type 2 diabetes mellitus (T2DM).

METHODS

This study included T2DM patients (n= 220, mean age 59 years) without a history of stroke or coronary artery disease. The brachial AWE, radial AWE, carotid mean intima-media thickness (IMT), max-IMT and flow-mediated vasodilation (FMD) were measured. The patients were classified according to the number of atherosclerotic risk factors, including obesity, dyslipidemia and hypertension. Group 1 included T2DM patients only, group 2 included patients with two risk factors, group 3 included patients with three risk factors and group 4 included patients with four risk factors. The patients were also divided into two groups according to microangiopathic complications, including retinopathy and nephropathy. The between-group differences were analyzed.

RESULTS

The brachial AWE (548, 697, 755 and 771 kPa for groups 1, 2, 3 and 4, respectively) and radial AWE (532, 637, 717 and 782 kPa for groups 1, 2, 3 and 4, respectively) significantly increased in association with an increasing number of risk factors. The brachial AWE and radial AWE were significantly higher in the patients with microangiopathic complications than in those without microangiopathic complications (brachial AWE 797 and 694 kPa and radial AWE 780 and 660 kPa, respectively). Receiver operating characteristic curve analyses revealed that, for brachial AWE and radial AWE, the area under the curve was equal to the max-IMT and higher than the mean-IMT and FMD.

CONCLUSIONS

Upper limb AWE measurement can reflect the degree of atherosclerosis risk overload and may be useful for evaluating vascular complications in T2DM patients.

Surface density mapping of natural tissue by a scanning haptic microscope (SHM)

To expand the performance capacity of the scanning haptic microscope (SHM) beyond surface mapping microscopy of elastic modulus or topography, surface density mapping of a natural tissue was performed by applying a measurement theory of SHM, in which a frequency change occurs upon contact of the sample surface with the SHM sensor - a microtactile sensor (MTS) that vibrates at a pre-determined constant oscillation frequency. This change was mainly stiffness-dependent at a low oscillation frequency and density-dependent at a high oscillation frequency. Two paragon examples with extremely different densities but similar macroscopic elastic moduli in the range of natural soft tissues were selected: one was agar hydrogels and the other silicon organogels with extremely low (less than 25 mg/cm(3)) and high densities (ca. 1300 mg/cm(3)), respectively. Measurements were performed in saline solution near the second-order resonance frequency, which led to the elastic modulus, and near the third-order resonance frequency. There was little difference in the frequency changes between the two resonance frequencies in agar gels. In contrast, in silicone gels, a large frequency change by MTS contact was observed near the third-order resonance frequency, indicating that the frequency change near the third-order resonance frequency reflected changes in both density and elastic modulus. Therefore, a density image of the canine aortic wall was subsequently obtained by subtracting the image observed near the second-order resonance frequency from that near the third-order resonance frequency. The elastin-rich region had a higher density than the collagen-rich region.