The relationship of peripheral arterial disease and metabolic syndrome prevalence in asymptomatic US adults 40 years and older: results from the National Health and Nutrition Examination Survey (1999-2004)

Association Between Metabolic Syndrome and Peripheral Arterial Disease in Elderly Patients with Type 2 Diabetes

BACKGROUND

Peripheral artery disease (PAD) is a manifestation of atherosclerotic cardiovascular disease (ASCVD) and significantly increases the risk of myocardial infarction and stroke. As most patients with PAD are asymptomatic, this condition is largely neglected in clinical practice. Type 2 diabetes (T2DM) patients have higher prevalence of PAD. Therefore, early detection and intervention of diabetic PAD are very important. Metabolic syndrome (MetS) is a group of interrelated metabolic risk factors, a predictor of poor prognosis in elderly patients with ASCVD. Recently, many of the metabolic risk factors as well as the overall concept of MetS itself have sparked a great deal of debate regarding their precise roles in PAD.

OBJECTIVE

To evaluate the relationship between metabolic syndrome (MetS) and peripheral arterial disease (PAD) in elderly patients with type 2 diabetes (T2DM).

METHODS

Two hundred and eighty-one elderly T2DM patients admitted to Beijing Tongren Hospital from October 2016 to December 2017 were divided into PAD group (n=136) and non-PAD (NPAD) group (n=145). Their medical records, physical examination parameters and laboratory testing parameters were later recorded and analyzed by multivariate logistic regression analysis.

RESULTS

No significant difference was detected in general clinical data and laboratory testing parameters between the two groups (P>0.05). The incidence of MetS was significantly higher in PAD group than in NPAD group (88.2% vs 70.3%, P=0.001). Multivariate logistic regression analysis showed that the risk of PAD was 1.762-fold higher in MetS patients after adjustment for age, sex, history of smoking and alcohol consumption, WC, SBP, serum TC and HbA1c level, eGFR and duration of DM (95% CI: 1.205-6.330, P=0.016).

CONCLUSION

MetS closely correlates with PAD in elderly T2DM patients, though no significant difference has been detected in their metabolic indicators.

Using the epidemiology of critical limb ischemia to estimate the number of patients amenable to endovascular therapy

Critical limb ischemia represents the advanced stage of peripheral artery disease, a health problem with increasing prevalence. Critical limb ischemia is associated with significant mortality, limb loss, pain, and diminished health-related quality of life. Public awareness and early diagnosis are necessary for an effective treatment with early risk factor modification, smoking cessation, and exercise therapy. Herein, we present an overview of the epidemiology as well as the clinical stages of the disease, and estimate that there are 6.5 million patients with critical limb ischemia in the US, Europe, and Japan based on global population-based studies. At least 75% of these patients, accounting for approximately 4.8 million patients, are amenable to endovascular therapy.

Subclinical atherosclerosis, cardiovascular health, and disease risk: is there a case for the Cardiovascular Health Index in the primary prevention population?

Background

Current primary prevention guidelines for cardiovascular disease (CVD) prioritize risk identification, risk stratification using clinical and risk scores, and risk reduction with lifestyle interventions and pharmacotherapy. Subclinical atherosclerosis is an early indicator of atherosclerotic burden and its timely recognition can slow or prevent progression to CVD. Thus, individuals with subclinical atherosclerosis are a priority for primary prevention. This study takes a practical approach to answering a challenge commonly faced by primary care practitioners: in patients with no known CVD, how can individuals likely to have subclinical atherosclerosis be easily identified using existing clinical data and/or information provided by the patient?

Methods

Using NHANES (1999–2004), 6091 men and women aged ≥40 years without any CVD comprised the primary prevention population for this study. Subclinical atherosclerosis was determined via ankle-brachial index (ABI) using established cutoffs (subclinical atherosclerosis defined as ABI (0.91–0.99); normal defined as ABI (1.00–1.30)). Three common scores were calculated: the Framingham Risk Score (FRS), the Metabolic Syndrome (MetS), and the Cardiovascular Health Index (CVHI). Logistic regression analysis assessed the association between these scores and subclinical atherosclerosis. The sensitively and specificity of these scores in identifying subclinical atherosclerosis was determined.

Results

In eligible participants, 3.8% had subclinical atherosclerosis. Optimum and average CVHI was associated with decreased odds for subclinical atherosclerosis. High, but not intermediate-risk, FRS was associated with increased odds for subclinical atherosclerosis. MetS was not associated with subclinical atherosclerosis. Of the 3 scores, CVHI was the most sensitive in identifying subclinical atherosclerosis and had the lowest number of missed cases. The FRS was the most specific but least sensitive of the 3 scores, and had almost 10-fold more missed cases vs. the CVHI. The MetS had “middle” sensitivity and specificity, and 10-fold more missed cases vs. the CVHI.

Conclusions

Results from this study suggest that routine administration of the CVHI in a primary prevention population would yield the benefits of identifying patients with existing subclinical CVD not identified through traditional CVD risk factors or scores, and bring physical activity and nutrition to the forefront of provider-patient discussions about lifestyle factors critical to maintaining and prolonging cardiovascular health.

Quantitative evaluation of graded hindlimb ischemia based on pharmacokinetic modelling and hemodynamic analysis of indocyanine green

OBJECTIVE

Accurate evaluation of the degree of hindlimb ischemia is challenging but essential for the diagnosis and treatment of peripheral vascular insufficiency. The aim of the study is to apply a multiparametric method for the quantitative estimation of mouse models with different degrees of hindlimb ischemia based on a dynamic fluorescence imaging-based strategy.

APPROACH

An adjustable hydraulic occluder was placed around the thigh root of one hindlimb to induce six different degrees of hindlimb ischemia. Five parameters were extracted to quantitatively evaluate the degree of ischemia, including perfusion rate (PR) and perfusion vascular density (PVD) from a mathematical model of indocyanine green (ICG) pharmacokinetics, rising time (T _rise), blood flow index (BFI) and mean fluorescence intensity (MFI) from time-series analysis of ICG hemodynamics.

MAIN RESULTS

The results showed that the normalized PR and BFI decreased while the normalized T _rise increased progressively with the degree of ischemia. The normalized PVD and MFI first increased and then decreased with the degree of ischemia. High correlation was observed between the degree of ischemia and the arterial oxygen saturation which was measured by an oximeter.

SIGNIFICANCE

The results of this work demonstrated that PR, BFI and T _rise can be used for the quantitative and comprehensive evaluation of graded hindlimb ischemia.

Correlation of ankle-brachial index and peripheral artery disease with the status of body fat deposition and metabolic syndrome in asymptomatic premenopausal women

INTRODUCTION

Asymptomatic peripheral artery disease (PAD) in symptom-free subjects, and people with the metabolic syndrome (MetS) is a significant correlate of cardiovascular morbidity and mortality. However, little is known about their relationship and whether this is mediated through central obesity as one of the defining components of the MetS.

MATERIALS AND METHODS

In a cross-sectional setting, 150 asymptomatic healthy premenopausal women without previously diagnosed hypertension, diabetes or known history cardiovascular diseases were consecutively enrolled. Ankle-brachial index (ABI), various parameters of general and central body fat distribution, and MetS were assessed.

RESULTS

The prevalence rates for asymptomatic PAD and MetS within the study population were calculated at 6% and 44%, respectively. Following the rigorous adjustment made by the components of MetS and clincial variables of age and serum low-density lipoprotein cholesterols (LDL-C), several indicators of general and central body fat distribution, including total, truncal and visceral body fats were found to have significantly positive correlations with log-ABI values. Moreover, log-ABI was significantly and negatively associated with the presence of MetS in both crude and multivariate models of logistic regression analysis, as adjusted by age, LDL-C and several indices of general and central fat deposition (OR [95% CI]: 0.016 [0.001 to 0.424], P value=0.013 in the multivariate adjusted model).

CONCLUSION

ABI had positive and negative associations with central obesity and MetS, respectively. Our findings strongly suggest the inverse correlation between ABI and the MetS is likely not mediated through central obesity as one the key components of MetS.

Interethnic Differences in Serum Lipids and Implications for Cardiometabolic Disease Risk in African Ancestry Populations

African Americans generally have a healthier lipid profile (lower triglycerides and higher high-density lipoprotein cholesterol concentration) compared with those of other ethnicities. Paradoxically, African Americans do not experience a decreased risk of the cardiometabolic diseases that serum lipids are expected to predict. This review explores this mismatch between biomarker and disease among African ancestry individuals by investigating the presence of interethnic differences in the biological relationships underlying the serum lipids-disease association. This review also discusses the physiologic and genomic factors underlying these interethnic differences. Additionally, because of the importance of serum lipids in assessing disease risk, interethnic differences in serum lipids have implications for identifying African ancestry individuals at risk of cardiometabolic disease. Where possible, data from Africa is included, to further elucidate these ancestral differences in the context of a different environmental background.

Multiparametric evaluation of hindlimb ischemia using time-series indocyanine green fluorescence imaging

Peripheral arterial disease (PAD) can further cause lower limb ischemia. Quantitative evaluation of the vascular perfusion in the ischemic limb contributes to diagnosis of PAD and preclinical development of new drug. In vivo time-series indocyanine green (ICG) fluorescence imaging can noninvasively monitor blood flow and has a deep tissue penetration. The perfusion rate estimated from the time-series ICG images is not enough for the evaluation of hindlimb ischemia. The information relevant to the vascular density is also important, because angiogenesis is an essential mechanism for post-ischemic recovery. In this paper, a multiparametric evaluation method is proposed for simultaneous estimation of multiple vascular perfusion parameters, including not only the perfusion rate but also the vascular perfusion density and the time-varying ICG concentration in veins. The target method is based on a mathematical model of ICG pharmacokinetics in the mouse hindlimb. The regression analysis performed on the time-series ICG images obtained from a dynamic reflectance fluorescence imaging system. The results demonstrate that the estimated multiple parameters are effective to quantitatively evaluate the vascular perfusion and distinguish hypo-perfused tissues from well-perfused tissues in the mouse hindlimb. The proposed multiparametric evaluation method could be useful for PAD diagnosis. The estimated perfusion rate and vascular perfusion density maps (left) and the time-varying ICG concentration in veins of the ankle region (right) of the normal and ischemic hindlimbs.

Lung function in elderly subjects with metabolic syndrome and type II diabetes : Data from the Berlin Aging Study II

BACKGROUND

Previous studies have indicated a relationship between type II diabetes (T2D), metabolic syndrome (MetS) and pulmonary function but the pathological mechanism responsible remains unclear. The aim of the current analysis within the Berlin Aging Study II (BASE-II) was to investigate the influence of abdominal obesity and muscle mass on pulmonary function in subjects with T2D and MetS.

MATERIAL AND METHODS

A prebronchodilator pulmonary function test was carried out in 1369 subjects from the BASE-II (mean age 69 ± 4 years, 51.6 % women) where T2D was defined according to the German Diabetes Association (DDG) criteria, MetS according to the criteria of the International Diabetes Foundation (IDF), American Heart Association (AHA) and National Heart, Lung and Blood Institute (NHLBI) criteria from 2009 and pulmonary obstruction (obstructive lung disease, OLD) by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria of a forced expiratory volume in 1 s (FEV1 and forced vital capacity (FVC) ratio < 70 %.

RESULTS

Of the subjects 50.9 % achieved a sufficient level of quality according to the GOLD guidelines and were analyzed with respect to the research question. The FEV1 and FVC were decreased in study participants with T2D and MetS and the lung volume decreased with an increasing number of MetS criteria. Parameters of body composition, such as waist circumference and muscle mass had a significant influence on lung volumes, independent of MetS or T2D.

DISCUSSION

In this study MetS and T2D were associated with decreased lung volumes; however, muscle mass and abdominal obesity proved to be the most important factors influencing pulmonary function and could thus form the link between pulmonary function and MetS or T2D. Measurement of grip strength for the determination of muscle mass and waist circumference for determining abdominal obesity could contribute to the interpretation of the results of pulmonary function tests.

Serum nesfatin-1 is reduced in type 2 diabetes mellitus patients with peripheral arterial disease

BACKGROUND

Nesfatin-1, recently identified as a satiety regulator, elicits an anti-atherosclerosis effect. Our study was designed to determine whether there is an association between serum nesfatin-1 and the development and severity of peripheral arterial disease (PAD) in patients with type 2 diabetes mellitus (T2DM).

MATERIAL AND METHODS

This cross-sectional study included 355 T2DM patients (200 without PAD and 155 with PAD).

RESULTS

T2DM patients with PAD exhibited marked lower serum nesfatin-1 concentrations than those without PAD. Multivariable logistic regression analysis indicated an inverse association of serum nesfatin-1 concentrations with the development of PAD in T2DM patients (OR 0.008, 95% CI 0.002 to 0.028; P<0.001). Simple linear regression analysis showed a marked correlation between serum nesfatin-1 concentrations and body mass index (BMI), homeostasis model assessment of insulin resistance (HOMA-IR), C-reactive protein (CRP), and ankle-brachial index (ABI) in T2DM patients. By contrast, multivariable analysis showed only BMI and ABI as independent correlates of serum nesfatin-1.

CONCLUSIONS

Our study shows an association of serum nesfatin-1 concentrations and the development and severity of PAD in T2DM patients.

Impact of weight loss on ankle-brachial index and interartery blood pressures

OBJECTIVE

To assess whether weight loss improves markers of peripheral artery disease and vascular stenosis.

METHODS

The Action for Health in Diabetes randomized clinical trial compared intensive lifestyle intervention (ILI) for weight loss to a control condition of diabetes support and education (DSE) in overweight or obese adults with type 2 diabetes. Annual ankle and brachial blood pressures over four years were used to compute ankle-brachial indices (ABIs) and to assess interartery blood pressure differences in 5018 participants.

RESULTS

ILI, compared to DSE, produced 7.8% (Year 1) to 3.6% (Year 4) greater weight losses. These did not affect prevalence of low (<0.90) ABI (3.60% in DSE versus 3.14% in ILI; P = 0.20) or elevated (>1.40) ABI (7.52% in DSE versus 7.59% in ILI: P = 0.90), but produced smaller mean (SE) maximum interartery systolic blood pressure differences among ankle sites [19.7 (0.2) mmHg for ILI versus 20.6 (0.2) mmHg for DSE (P < 0.001)] and between arms [5.8 (0.1) mmHg for ILI versus 6.1 (0.1) mmHg for DSE (P = 0.01)].

CONCLUSIONS

Four years of intensive behavioral weight loss intervention did not significantly alter prevalence of abnormal ABI, however, it did reduce differences in systolic blood pressures among arterial sites.

Association of calcaneal quantitative ultrasound parameters with metabolic syndrome in middle-aged and elderly Chinese: a large population-based cross-sectional study

BACKGROUND

The possible association between metabolic syndrome (MS) and bone mineral density (BMD) has been highlighted recently. However, the exact effects of MS on calcaneal quantitative ultrasound (QUS) parameters remains uncertain. The aim of this study was to assess the impact of MS states, different componets of MS, as well as the number of MS componets on QUS.

METHODS

A total of 7489 Chinese adults aged 40 years or older in Nanjing were enrolled in this cross-sectional study. MS was defined according to recommendations generated by the International Diabetes Federation (IDF) in 2005. QUS was measured for each participant.

RESULTS

The prevalence of MS was 34.6% in men and 42.8% in women (over 40 years old). In postmenopausal women with MS, 25-hydroxyvitamin D[25(OH)D], age adjusted quantitative ultrasound index (QUI) and broadband ultrasound attenuation (BUA) were all lower than those without (p < 0.001, p = 0.023, p = 0.021, respectively), the difference of QUI and BUA disappeared after adjustment for body mass index (BMI) and waist circumference (WC). In stepwise analysis, BMI, WC, high density lipoprotein cholesterol (HDL-C) and fasting plasma glucose (FPG) were related to QUS (p < 0.05). The number of MS components had no influence on QUS. Fragile fracture incidence was higher in women with MS (6.8% VS. 5.3%, P = 0.034).

CONCLUSION

Chinese postmenopausal women with MS have worse BMD measured by QUS and more chances to develop osteoporotic fractures than the controls, which partially due to central obesity as well as vitamin D deficiency. People having less central obesity, higher FPG or HDL-C are less likely to have bone mineral loss.

Pravastatin stimulates angiogenesis in a murine hindlimb ischemia model: a positron emission tomography imaging study with (64)Cu-NOTA-TRC105

In this study, (64)Cu-NOTA-TRC105 (TRC105 is an anti-CD105 monoclonal antibody that binds to both human and murine CD105) positron emission tomography (PET) was used to assess the response to pravastatin treatment in a murine model of peripheral artery disease (PAD). Hindlimb ischemia was induced by ligation of the right femoral arteries in BALB/c mice under anesthesia, and the left hindlimb served as an internal control. Mice in the treatment group were given intraperitoneal pravastatin daily until the end of the study, whereas the animals in the control group were injected with 0.9% sodium chloride solution. Laser Doppler imaging showed that blood flow in the ischemic hindlimb plummeted to ~20% of the normal level after surgery, and gradually recovered to near normal level on day 10 in the treatment group and on day 20 in the control group. Angiogenesis was non-invasively monitored and quantified with (64)Cu-NOTA-TRC105 PET on postoperative days 3, 10, 17, and 24. Tracer uptake at 48 h post-injection in the ischemic hindlimb in the treatment group was significantly higher than that of the control group on day 10 (20.5 ± 1.9 %ID/g vs 11.4 ± 1.5 %ID/g), suggesting increased CD105 expression and higher level of angiogenesis upon pravastatin treatment, and gradually decreased to background levels in both groups (4.9 ± 0.8 %ID/g vs 3.4 ± 1.9 %ID/g on day 24). The in vivo PET data correlated well with ex vivo biodistribution studies performed on day 24. Increased CD105 expression on days 3 and 10 following ischemia was further confirmed by immunofluorescence staining. Taken together, our results indicated that (64)Cu-NOTA-TRC105 PET is a suitable and non-invasive method to monitor the angiogenesis and therapeutic response in PAD, which can also be utilized for non-invasive evaluation of other pro-angiogenic/anti-angiogenic drugs in other cardiovascular diseases and cancer.

T-cadherin is essential for adiponectin-mediated revascularization

Adipose tissue secretes protein factors that have systemic actions on cardiovascular tissues. Previous studies have shown that ablation of the adipocyte-secreted protein adiponectin leads to endothelial dysfunction, whereas its overexpression promotes wound healing. However, the receptor(s) mediating the protective effects of adiponectin on the vasculature is not known. Here we examined the role of membrane protein T-cadherin, which localizes adiponectin to the vascular endothelium, in the revascularization response to chronic ischemia. T-cadherin-deficient mice were analyzed in a model of hind limb ischemia where blood flow is surgically disrupted in one limb and recovery is monitored over 28 days by laser Doppler perfusion imaging. In this model, T-cadherin-deficient mice phenocopy adiponectin-deficient mice such that both strains display an impaired blood flow recovery compared with wild-type controls. Delivery of exogenous adiponectin rescued the impaired revascularization phenotype in adiponectin-deficient mice but not in T-cadherin-deficient mice. In cultured endothelial cells, T-cadherin deficiency by siRNA knockdown prevented the ability of adiponectin to promote cellular migration and proliferation. These data highlight a previously unrecognized role for T-cadherin in limb revascularization and show that it is essential for mediating the vascular actions of adiponectin.

Positron emission tomography imaging of angiogenesis in a murine hindlimb ischemia model with 64Cu-labeled TRC105

The goal of this study was to assess ischemia-induced angiogenesis with (64)Cu-NOTA-TRC105 positron emission tomography (PET) in a murine hindlimb ischemia model of peripheral artery disease (PAD). CD105 binding affinity/specificity of NOTA-conjugated TRC105 (an anti-CD105 antibody) was evaluated by flow cytometry, which exhibited no difference from unconjugated TRC105. BALB/c mice were anesthetized, and the right femoral artery was ligated to induce hindlimb ischemia, with the left hindlimb serving as an internal control. Laser Doppler imaging showed that perfusion in the ischemic hindlimb plummeted to ∼ 20% of the normal level after surgery and gradually recovered to near normal level on day 24. Ischemia-induced angiogenesis was noninvasively monitored and quantified with (64)Cu-NOTA-TRC105 PET on postoperative days 1, 3, 10, 17, and 24. (64)Cu-NOTA-TRC105 uptake in the ischemic hindlimb increased significantly from the control level of 1.6 ± 0.2 %ID/g to 14.1 ± 1.9 %ID/g at day 3 (n = 3) and gradually decreased with time (3.4 ± 1.9 %ID/g at day 24), which correlated well with biodistribution studies performed on days 3 and 24. Blocking studies confirmed the CD105 specificity of tracer uptake in the ischemic hindlimb. Increased CD105 expression on days 3 and 10 following ischemia was confirmed by histology and reverse transcription polymerase chain reaction (RT-PCR). This is the first report of PET imaging of CD105 expression during ischemia-induced angiogenesis. (64)Cu-NOTA-TRC105 PET may play multiple roles in future PAD-related research and improve PAD patient management by identifying the optimal timing of treatment and monitoring the efficacy of therapy.

PET/SPECT imaging of hindlimb ischemia: focusing on angiogenesis and blood flow

Peripheral artery disease (PAD) is a result of the atherosclerotic narrowing of blood vessels to the extremities, and the subsequent tissue ischemia can lead to the up-regulation of angiogenic growth factors and formation of new vessels as a recovery mechanism. Such formation of new vessels can be evaluated with various non-invasive molecular imaging techniques, where serial images from the same subjects can be obtained to allow the documentation of disease progression and therapeutic response. The most commonly used animal model for preclinical studies of PAD is the murine hindlimb ischemia model, and a number of radiotracers have been investigated for positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging of PAD. In this review article, we summarize the PET/SPECT tracers that have been tested in the murine hindlimb ischemia model as well as those used clinically to assess the extremity blood flow.