Glucose, insulin, diabetes and mechanisms of arterial dysfunction

Prenatal Effects of Nicotine on Obesity Risks: A Narrative Review

Nicotine usage by mothers throughout pregnancy has been observed to relate to numerous deleterious effects in children, especially relating to obesity. Children who have prenatally been exposed to nicotine tend to have lower birth weights, with an elevated risk of becoming overweight throughout development and into their adolescent and adult life. There are numerous theories as to how this occurs: catch-up growth theory, thrifty phenotype theory, neurotransmitter or endocrine imbalances theory, and a more recent examination on the genetic factors relating to obesity risk. In addition to the negative effect on bodyweight and BMI, individuals with obesity may also suffer from numerous comorbidities involving metabolic disease. These may include type 1 and 2 diabetes, high cholesterol levels, and liver disease. Predisposition for obesity with nicotine usage may also be associated with genetic risk alleles for obesity, such as the DRD2 A1 variant. This is important for prenatally nicotine-exposed individuals as an opportunity to provide early prevention and intervention of obesity-related risks.

Early Alterations of Intra-Mural Elastic Lamellae Revealed by Synchrotron X-ray Micro-CT Exploration of Diabetic Aortas

Diabetes is a major concern of our society as it affects one person out of 11 around the world. Elastic fiber alterations due to diabetes increase the stiffness of large arteries, but the structural effects of these alterations are poorly known. To address this issue, we used synchrotron X-ray microcomputed tomography with in-line phase contrast to image in three dimensions C57Bl6J (control) and db/db (diabetic) mice with a resolution of 650 nm/voxel and a field size of 1.3 mm³. Having previously shown in younger WT and db/db mouse cohorts that elastic lamellae contain an internal supporting lattice, here we show that in older db/db mice the elastic lamellae lose this scaffold. We coupled this label-free method with automated image analysis to demonstrate that the elastic lamellae from the arterial wall are structurally altered and become 11% smoother (286,665 measurements). This alteration suggests a link between the loss of the 3D lattice-like network and the waviness of the elastic lamellae. Therefore, waviness measurement appears to be a measurable elasticity indicator and the 3D lattice-like network appears to be at the origin of the existence of this waviness. Both could be suitable indicators of the overall elasticity of the aorta.

Negative Correlation of Serum Adiponectin Level with Aortic Stiffness in Elderly Diabetic Persons

Adiponectin has anti-inflammatory activity against atherosclerosis. Aortic stiffness is a common manifestation of atherosclerosis in diabetes mellitus and elderly persons. This study aimed to evaluate whether low serum adiponectin levels were associated with aortic stiffness in geriatric diabetic patients. Blood samples were obtained from 130 diabetic participants aged ≥ 65 years. We defined high aortic stiffness based on a carotid−femoral pulse wave velocity (cfPWV) of >10 m/s. Circulating adiponectin concentrations were examined using enzyme-linked immunosorbent assays. Sixty-six participants (50.8%) had aortic stiffness. Patients with aortic stiffness had lower serum adiponectin concentrations than those in the control group (p < 0.001). Multivariate logistic regression analysis showed that the adiponectin level (odds ratio: 0.939, 95% confidence interval: 0.898−0.981, p = 0.005) was an independent predictor of aortic stiffness in elderly diabetic persons. Multivariate forward stepwise linear regression analysis also demonstrated that the adiponectin level (β = −0.256, adjusted R2 change = 0.100, p = 0.003) was negatively associated with cfPWV values in older diabetic patients. In conclusion, serum adiponectin is negatively correlated with cfPWV and is an independent predictor of aortic stiffness in elderly diabetic persons.

Glycated Hemoglobin and Risk of Arterial Stiffness in a Chinese Han Population: A Longitudinal Study

BACKGROUND AND AIMS

Glycated hemoglobin (HbA1c) associates with the risk of arterial stiffness, and such association can be found between fasting blood glucose (FBG), postprandial blood glucose (PBG), triglyceride-glucose index (TyG index), and arterial stiffness. However, the results were inconsistent, longitudinal studies were sparse, and comparison of these glycemic parameters was less conducted. We aimed to explore the longitudinal relationship between HbA1c and arterial stiffness and compare the effect of the parameters.

METHODS

Data were collected from 2011 to 2019 in Beijing Health Management Cohort (BHMC) study. Cox proportional hazard models were fitted to investigate the association between the parameters and arterial stiffness. A generalized estimation equation (GEE) analysis was conducted to investigate the effect of repeated measurements of glycemic parameters. A receiver operating characteristic (ROC) analysis was performed to compare the predictive value of glycemic parameters for arterial stiffness.

RESULTS

Among 3,048 subjects, 591 were diagnosed as arterial stiffness during the follow-up. The adjusted hazard ratio (HR) [95% confidence interval (CI)] for arterial stiffness of the highest quartile group of HbA1c was 1.63 (1.22-2.18), which was higher than those of FBG, PBG, and TyG index. The nonlinear association of arterial stiffness with HbA1c and PBG was proved. The robust results of the sensitivity analysis were obtained.

CONCLUSIONS

HbA1c is an important risk factor of arterial stiffness compared with PBG, FBG, and TyG index, and has a strong predictive ability for arterial stiffness among non-diabetics and the general population.

Arterial Stiffness and Type 1 Diabetes: The Current State of Knowledge

The most common cause of mortality among people with type 1 diabetes is cardiovascular diseases. Arterial stiffness allows predicting cardiovascular complications, cardiovascular mortality, and all-cause mortality. There are different ways to measure arterial stiffness; the gold standard is pulse wave velocity. Arterial stiffness is increased in people with type 1 diabetes compared to healthy controls. It increases with age and duration of type 1 diabetes. Arterial stiffness among people with type 1 diabetes positively correlates with systolic blood pressure, obesity, glycated hemoglobin, waist circumference, and waist to hip ratio. It has a negative correlation with the estimated glomerular filtration rate, high-density lipoprotein, and the absence of carotid plaques. The increased arterial stiffness could result from insulin resistance, collagen increase due to inadequate enzymatic glycation, and endothelial and autonomic dysfunction. The insulin-induced decrease in arterial stiffness is impaired in type 1 diabetes. There are not enough proofs to use pharmacotherapy in the prevention of arterial stiffness, but some of the medicaments got promising results in single studies, for example, renin-angiotensin-aldosterone system inhibitors, statins, and SGLT2 inhibitors. The main strategy of prevention of arterial stiffness progression remains glycemic control and a healthy lifestyle.

Vascular Stiffness in Aging and Disease

The goal of this review is to provide further understanding of increased vascular stiffness with aging, and how it contributes to the adverse effects of major human diseases. Differences in stiffness down the aortic tree are discussed, a topic requiring further research, because most prior work only examined one location in the aorta. It is also important to understand the divergent effects of increased aortic stiffness between males and females, principally due to the protective role of female sex hormones prior to menopause. Another goal is to review human and non-human primate data and contrast them with data in rodents. This is particularly important for understanding sex differences in vascular stiffness with aging as well as the changes in vascular stiffness before and after menopause in females, as this is controversial. This area of research necessitates studies in humans and non-human primates, since rodents do not go through menopause. The most important mechanism studied as a cause of age-related increases in vascular stiffness is an alteration in the vascular extracellular matrix resulting from an increase in collagen and decrease in elastin. However, there are other mechanisms mediating increased vascular stiffness, such as collagen and elastin disarray, calcium deposition, endothelial dysfunction, and the number of vascular smooth muscle cells (VSMCs). Populations with increased longevity, who live in areas called “Blue Zones,” are also discussed as they provide additional insights into mechanisms that protect against age-related increases in vascular stiffness. Such increases in vascular stiffness are important in mediating the adverse effects of major cardiovascular diseases, including atherosclerosis, hypertension and diabetes, but require further research into their mechanisms and treatment.

Building Biomimetic Potency Tests for Islet Transplantation

Diabetes is a disease of insulin insufficiency, requiring many to rely on exogenous insulin with constant monitoring to avoid a fatal outcome. Islet transplantation is a recent therapy that can provide insulin independence, but the procedure is still limited by both the availability of human islets and reliable tests to assess their function. While stem cell technologies are poised to fill the shortage of transplantable cells, better methods are still needed for predicting transplantation outcome. To ensure islet quality, we propose that the next generation of islet potency tests should be biomimetic systems that match glucose stimulation dynamics and cell microenvironmental preferences and rapidly assess conditional and continuous insulin secretion with minimal manual handing. Here, we review the current approaches for islet potency testing and outline technologies and methods that can be used to arrive at a more predictive potency test that tracks islet secretory capacity in a relevant context. With the development of potency tests that can report on islet secretion dynamics in a context relevant to their intended function, islet transplantation can expand into a more widely accessible and reliable treatment option for individuals with diabetes.

Determinants of change in arterial stiffness over 5 years in early chronic kidney disease

BACKGROUND

Arterial stiffness (AS) is an established and potentially modifiable risk factor for cardiovascular disease associated with chronic kidney disease (CKD). There have been few studies to evaluate the progression of AS over time or factors that contribute to this, particularly in early CKD. We therefore investigated AS over 5 years in an elderly population with CKD Stage 3 cared for in primary care.

METHODS

A total of 1741 persons with an estimated glomerular filtration rate of 30-59 mL/min/1.73 m2 underwent detailed clinical and biochemical assessment at baseline and Years 1 and 5. Carotid to femoral pulse wave velocity (PWV) was measured to assess AS using a Vicorder device.

RESULTS

970 participants had PWV assessments at baseline and 5 years. PWV increased significantly by a mean of 1.1 m/s (from 9.7 ± 1.9 to 10.8 ± 2.1 m/s). Multivariable linear regression analysis identified the following independent determinants of ΔPWV at Year 5: baseline age, diabetes status, baseline systolic blood pressure (SBP) and diastolic blood pressure, baseline PWV, ΔPWV at 1 year, ΔSBP over 5 years and Δserum bicarbonate over 5 years (R2 = 0.38 for the equation).

CONCLUSIONS

We observed a clinically significant increase in PWV over 5 years in a cohort with early CKD despite reasonably well-controlled hypertension. Measures of BP were identified as the most important modifiable determinant of ΔPWV, suggesting that interventions to prevent arterial disease should focus on improved control of BP, particularly in those who evidence an early increase in PWV. These hypotheses should now be tested in prospective trials.

Hyperglycemia and arterial stiffness across two generations

OBJECTIVE

Hyperglycemia and diabetes mellitus associate with arterial stiffness. This observational study aimed to investigate such links in two related generations from a population-based study.

METHODS

Data from 2640 participants in the ongoing Malmö Offspring Study, Sweden, was used. The participants were direct descendants, that is, parents (median age 52.5 years) and children (26.9 years). In linear regressions, arterial stiffness measured through carotid--femoral pulse wave velocity was associated with markers of glucose metabolism (fasting glucose, glycated hemoglobin, skin autoflourescence of Advanced Glycation End products), adjusted for age, sex, smoking, BMI, lipids, SBP and antihypertensive medication. Analysis was first performed in all participants and then separately in each generation. T-tests with diabetes mellitus as the grouping variable were performed for all participants and per generation.

RESULTS

In all participants, pulse wave velocity was significantly associated with glucose (β = 0.007, P = 0.018) and hemoglobin (β = 0.017, P < 0.001), but not with autoflourescence. Stratified by generation, arterial stiffness was associated with glucose (β = 0.013, P = 0.008) and glycated hemoglobin (β = 0.022, P < 0.001) only in parents. Mean pulse speed differed between participants with and without diabetes in the total group (mean difference 1.7 m/s, P < 0.001), as well as within each generation (parents: 1.3 m/s; P < 0.001, and children: 0.7 m/s; P = 0.040).

CONCLUSION

Impaired glucose metabolism and arterial stiffness were significantly associated only in the parental generation, indicating the influence of hyperglycemia on vascular aging. However, carotid--femoral pulse wave velocity differed significantly between participants with or without diabetes mellitus in both generations, suggesting that diabetes might negatively affect arterial stiffness also at a younger age.

Common carotid pulsatility is deteriorated by autoimmune thyroiditis in children with type 1 diabetes mellitus - A pilot study

Autoimmune thyroiditis (AIT) frequently coexists with type 1 diabetes (DM1) and additionally increases the extent of microcirculatory complications due to DM1. We hypothesized that in pediatric patients with DM1, impairment of macrocirculation could be further augmented by a coexisting autoimmune process. Therefore, we investigated the influence of AIT on large arteries in DM1 pediatric patients. Our group consisted of 19 DM1, 19 DM1 + AIT patients and 29 control subjects. The groups were comparable regarding age and gender. The DM1 and DM1 + AIT patients were matched for age at onset of DM1 and diabetes duration. Macrocirculation was described using pulsatility indices (PIs) determined for common carotid (CCA) and peripheral arteries of upper and lower limbs. CCA resistance index (RI) and ABI were also assessed. Children with DM1 + AIT had only significantly lower CCA_PI and CCA_RI in comparison with controls whereas in the absence of AIT such difference was not found. The diabetes duration and age of onset did not correlate with carotid indices. Total cholesterol level was higher both in DM1 + AIT and DM1 groups than in the control group. For low density lipoproteins cholesterol, a significant difference was found between DM1 + AIT and control groups. Age-independent impact of AIT on CCA_PI was confirmed by multivariate analysis. Common carotid pulsatility is deteriorated by autoimmune thyroiditis independently of age in children with type 1 diabetes mellitus.

Electroencephalogram Reactivity to Hyperglycemia in Patients with Type 1 Diabetes

This paper is concerned with a study of hyperglycemia on four patients with type 1 diabetes at night time. We investigated the association between hyperglycemic episodes and electroencephalogram (EEG) signals using data from the central and occipital areas. The power spectral density of the brain waves was estimated to compare the difference between hyperglycemia and euglycemia using the hyperglycemic threshold of 8.3 mmol/L. The statistical results showed that alpha and beta bands were more sensitive to hyperglycemic episodes than delta and theta bands. During hyperglycemia, whereas the alpha power increased significantly in the occipital lobe (P<0.005), the power of the beta band increased significantly in all observed channels (P<0.01). Using the Pearson correlation, we assessed the relationship between EEG signals and glycemic episodes. The estimated EEG power levels of the alpha band and the beta band produced a significant correlation against blood glucose levels (P<0.005). These preliminary results show the potential of using EEG signals as a biomarker to detect hyperglycemia.

Substrate stiffness-dependent exacerbation of endothelial permeability and inflammation: mechanisms and potential implications in ALI and PH (2017 Grover Conference Series)

The maintenance of endothelial barrier integrity is absolutely essential to prevent the vascular leak associated with pneumonia, pulmonary edema resulting from inhalation of toxins, acute elevation to high altitude, traumatic and septic lung injury, acute lung injury (ALI), and its life-threatening complication, acute respiratory distress syndrome (ARDS). In addition to the long-known edemagenic and inflammatory agonists, emerging evidences suggest that factors of endothelial cell (EC) mechanical microenvironment such as blood flow, mechanical strain of the vessel, or extracellular matrix stiffness also play an essential role in the control of endothelial permeability and inflammation. Recent studies from our group and others have demonstrated that substrate stiffening causes endothelial barrier disruption and renders EC more susceptible to agonist-induced cytoskeletal rearrangement and inflammation. Further in vivo studies have provided direct evidence that proinflammatory stimuli increase lung microvascular stiffness which in turn exacerbates endothelial permeability and inflammation and perpetuates a vicious circle of lung inflammation. Accumulating evidence suggests a key role for RhoA GTPases signaling in stiffness-dependent mechanotransduction mechanisms defining EC permeability and inflammatory responses. Vascular stiffening is also known to be a key contributor to other cardiovascular diseases such as arterial pulmonary hypertension (PH), although the precise role of stiffness in the development and progression of PH remains to be elucidated. This review summarizes the current understanding of stiffness-dependent regulation of pulmonary EC permeability and inflammation, and discusses potential implication of pulmonary vascular stiffness alterations at macro- and microscale in development and modulation of ALI and PH.

Efficacy and safety of American ginseng (Panax quinquefolius L.) extract on glycemic control and cardiovascular risk factors in individuals with type 2 diabetes: a double-blind, randomized, cross-over clinical trial

PURPOSE

Despite the lack of evidence, a growing number of people are using herbal medicine to attenuate the burden of diabetes. There is an urgent need to investigate the clinical potential of herbs. Preliminary observations suggest that American ginseng (Panax quinquefolius [AG]) may reduce postprandial glycemia. Thus, we aimed to evaluate the efficacy and safety of AG as an add-on therapy in individuals with type 2 diabetes (T2DM) controlled by conventional treatment.

METHODS

24 individuals living with T2DM completed the study (F:M = 11:13; age = 64 ± 7 year; BMI = 27.8 ± 4.6 kg/m²; HbA1c = 7.1 ± 1.2%). Utilizing a double-blind, cross-over design, the participants were randomized to receive either 1 g/meal (3 g/day) of AG extract or placebo for 8 weeks while maintaining their original treatment. Following a ≥ 4-week washout period, the participants were crossed over to the opposite 8-week treatment arm. The primary objective was HbA1c, and secondary endpoints included fasting blood glucose and insulin, blood pressure, plasma lipids, serum nitrates/nitrites (NOx), and plasominogen-activating factor-1 (PAI-1). Safety parameters included liver and kidney function.

RESULTS

Compared to placebo, AG significantly reduced HbA1c (- 0.29%; p = 0.041) and fasting blood glucose (- 0.71 mmol/L; p = 0.008). Furthermore, AG lowered systolic blood pressure (- 5.6 ± 2.7 mmHg; p < 0.001), increased NOx (+ 1.85 ± 2.13 µmol/L; p < 0.03), and produced a mean percent end-difference of - 12.3 ± 3.9% in LDL-C and - 13.9 ± 5.8% in LDL-C/HDL. The safety profiles were unaffected.

CONCLUSIONS

AG extract added to conventional treatment provided an effective and safe adjunct in the management of T2DM. Larger studies using physiologically standardized ginseng preparations are warranted to substantiate the present findings and to demonstrate therapeutic effectiveness of AG. CLINICALTRIALS.

GOV IDENTIFIER

NCT02923453.

Association between long-term blood pressure control and ten-year progression in carotid arterial stiffness among hypertensive individuals: the multiethnic study of atherosclerosis

BACKGROUND

Arterial stiffness was shown to be higher among hypertensive patients with diabetes than those without diabetes and among older than younger hypertensive patients. We examined whether the association between long-term blood pressure (BP) control and 10-year progression in carotid arterial stiffness varies by diabetes status and age.

METHODS

Participants were 906 individuals with hypertension at baseline and three follow-up visits in the Multi-Ethnic Study of Atherosclerosis (mean age 63.7 years, 44% males). Participants with SBP of less than 140 mmHg and DBP of less than 90 mmHg were considered to have a controlled BP. Arterial stiffness was measured using distensibility coefficient × 10/mmHg and Young's elastic modulus (YEM × 10 mmHg) at baseline and after a mean of 9.5 years (visit 5). Multiple linear regression model was used for the analysis.

RESULTS

Having controlled BP at three visits (distensibility coefficient: β = 3.6, P = 0.004; YEM: β = -6.8, P = 0.07) or four visits (distensibility coefficient: β = 2.4, P = 0.04; YEM: β = -6.8, P = 0.05), when compared with having uncontrolled BP at all four visit, was associated with lesser progression in arterial stiffness. In a stratified analysis, arterial stiffness progression was slower only among nondiabetics with controlled BP at three visits (distensibility coefficient: β = 4.3, P = 0.002; YEM: β = -8.8, P = 0.04) or four visits (β = 3.7, P = 0.01; YEM: β = -10.4, P = 0.01) and among those less than 70 years with controlled BP at three visits (distensibility coefficient: β = 4.9, P = 0.004; YEM: β = -10.6, P = 0.01) or four visits (distensibility coefficient: β = 2.9, P = 0.07; YEM: β = -7.6, P = 0.03).

CONCLUSION

These findings suggest that controlling BP alone may not be sufficient to slow progression of arterial stiffness among hypertensive patients with concurrent diabetes and elderly hypertensive patients.

Roles of fasting and postprandial blood glucose in the effect of type 2 diabetes on central arterial stiffness: a 5-year prospective community-based analysis

BACKGROUND

Cardiovascular disease constitutes a major challenge for the health of community-dwelling population, it is essential to delay the development of atherosclerosis. However, long-term prospective studies analyzing the effect of type 2 diabetes (T2D) on central arterial stiffness are lacking, and roles of fasting and postprandial blood glucose (FBG and PBG) in this effect are controversial. Purpose of the current analysis was to investigate the effect of T2D on central arterial stiffness during the 5 years of follow-up, and explore whether both FBG and PBG were determinants of this effect in Chinese community-dwelling population.

METHODS

The current analysis involved 898 individuals with carotid-femoral pulse wave velocity (cfPWV) ≤12 m/s. Central arterial stiffness was assessed by standard cfPWV at baseline and follow-up.

RESULTS

Incidence of cfPWV >12 m/s was 21.3% (102 participants). Participants without T2D had an increase of cfPWV with a median of 0.6 m/s, whereas participants with T2D had an increase of cfPWV with a median of 1.2 m/s (p = 0.007). T2D had an independent effect on increased cfPWV in multivariate Logistic regression models (p < 0.05 for all). Elevated levels of both FBG and PBG determined the independent effect on increased cfPWV in multivariate linear regression models (p < 0.05 for all).

CONCLUSIONS

Type 2 diabetes had an independent effect on the development of central arterial stiffness in Chinese community-dwelling population. Both FBG and PBG should be responsible for the development of central arterial stiffness and treated as the targets of glycemic control.

Impaired endothelial function and arterial stiffness in patients with type 2 diabetes - The effect of a very low-dose combination of fluvastatin and valsartan

AIM

Patients with type 2 diabetes are at increased cardiovascular risk. The aim was to explore whether the impaired arterial wall characteristics typical of these patients could be improved by the unique beneficial effects of a very low-dose combination of fluvastatin and valsartan (low-flu/val).

METHODS

Forty middle-aged males (50.4±6.1years) with type 2 diabetes were recruited to a double-blind, randomized study. Patients (N=20) received low-flu/val (10/20mg) or placebo (N=20) over 30days in addition to their regular therapy. Brachial artery flow mediated dilation (FMD), common carotid artery pulse wave velocity (PWV) and β-stiffness were assessed before and after treatment, and 3 and 6months after treatment discontinuation. The treatment was then repeated.

RESULTS

Arterial wall characteristics significantly improved. After 30days of intervention, FMD increased from 2.4±0.3 to 4.2±0.3 (p<0.001), PWV decreased from 6.4±0.1 to 5.8±0.2 (p<0.001) and β stiffness decreased from 7.8±0.4 to 6.7±0.4 (p<0.001). Lipids and arterial pressure did not change. After treatment discontinuation, the beneficial effects decreased over the following months. The repetition of treatment completely regained the initial benefits. No changes were observed in the placebo group.

CONCLUSIONS

Low-flu/val added on-top of optimal therapy substantially improves arterial wall characteristics in patients with type 2 diabetes.

Arterial Disease and Vascular Access in Diabetic Patients

Purpose

There are conflicting reports on the effects of diabetes on the outcomes of hemodialysis access procedures. While some found no negative effects, others reported deleterious effects of diabetes on vascular access outcomes. Why is there concern about diabetes and related vascular problems on vascular access procedures? What are the differences of diabetic patients and their vasculature from that of nondiabetics? Do they have an effect on hemodialysis vascular access outcomes? We will try to find answers to these questions in light of the available evidence.

Methods

Recent literature on arterial disease in diabetes and end-stage renal disease (ESRD), and the effects on vascular access outcomes were searched in order to find answers to above questions.

Results

There are conflicting and controversial reports on the effects of preexisting vascular problems due to diabetes and chronic kidney disease (CKD) on the outcomes of hemodialysis access procedures. Diabetic vasculature, especially in patients with ESRD, has some specific problems, the most important of which seem to be the calcification and stiffening of the arteries.

Conclusions

Although some authors report inferior outcomes of vascular access procedures in diabetic patients, there is evidence that most of the problems encountered can be dealt with by careful patient selection, surgical skill, and experience.

High glucose regulates LN expression in human liver sinusoidal endothelial cells through ROS/integrin αvβ3 pathway

Diabetes mellitus can cause a wide variety of vascular complications and is one of the major risk factors for Non Alcoholic Fatty Liver Disease (NAFLD). The present study was designed investigate the expression of laminin (LN) in human liver sinusoidal endothelial cells (HLSECs) induced by high glucose and the role of reactive oxygen species (ROS) and integrin αvβ3 in the regulation of LN expression. HLSECs were cultured and treated with media containing 25 mM glucose in the presence or absence of N-acetylcysteine (NAC) or clone LM609. The level of intracellular ROS of HLSECs was measured with 2',7' dichloro-fluorescein diacetate (DCFH-DA) probe. Expression of integrin αvβ3 was measured using RT-PCR and Western blot. Expression of LN was testified by immunofluorescence assay. Compared with that in control group, ROS level and the expression of integrin αvβ3 and LN increased in high glucose group. Compared with that in high glucose group, antioxidant NAC inhibited the expression of integrin αvβ3, NAC and the anti-body for blocking integrin αvβ3 (clone LM609) down-regulated the expression of LN. However, the above parameters did not differ between control and mannitol groups. High glucose up-regulates expression of LN in HLSECs through ROS/integrin αvβ3 pathway.

Complications and comorbidities of T2DM in adolescents: findings from the TODAY clinical trial

With the rise in childhood obesity, type 2 diabetes mellitus (T2DM) has been recognized to occur in adolescents with increasing frequency. Although much is known about T2DM in adults, few studies have examined the treatment and complications of T2DM in youth. The Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study was designed to evaluate the efficacy of various treatments and provided a unique opportunity to study the disease progression and appearance of complications in a pediatric cohort with recent onset of the disease. In the TODAY study, hypertension was present in 11.6% of the population at baseline and increased to 33.8% by the end of the study. Prevalence of high-risk LDL-cholesterol rose from 4.5% at baseline to 10.7% at the end of the study. Microalbuminuria was found in 6.3% of the cohort at baseline and increased to 16.6%. Retinopathy was not assessed upon entry into TODAY, but was present in 13.9% of the TODAY cohort at the end of the study. Experience to date indicates that these complications and comorbidities are similar to those seen in adults, but occur on an accelerated timeline. The early manifestation of diabetes complications in youth-onset T2DM suggests that this group will be burdened with the tangible consequences of cardiovascular disease, nephropathy, and retinopathy in the third and fourth decades of life. It is hoped that through an early, aggressive approach to treatment and prevention, we may be able to curb the onset and progression of these potentially devastating outcomes.

A cross-sectional assessment to detect type 2 diabetes with endothelial and autonomic nervous system markers using a novel system

Background

Type 2 diabetes mellitus is frequently unrecognized until complications appear. Diabetic autonomic neuropathy is one of the early complications of type 2 diabetes mellitus, resulting in autonomic nervous system (ANS) dysfunction. The purpose of this study was to determine the validity of ANS function indicators to screen for type 2 diabetes mellitus, as measured by the TM-Oxi and SudoPath system.

Methods

All enrolled participants completed a basic sociodemographic and medical history questionnaire including current medications. Healthy controls (n = 25) underwent a 2-hour oral glucose tolerance test (OGTT) to evaluate glucose, insulin, and insulin C-peptide. Patients with type 2 diabetes mellitus (n = 24) were assessed with fasting plasma glucose (FPG) and glycosylated hemoglobin. The TM-Oxi and SudoPath system evaluation was completed by all subjects. Data were analyzed using SPSS 22. Frequency and descriptive statistics were calculated on all variables. The criterion for statistical significance was α = 0.05.

Results

The twenty-five healthy controls had a mean age of 37.0 years. The twenty-four type 2 diabetes mellitus patients currently undergoing standard treatment had a mean age of 48.9 years. Based on the American Diabetes Association guidelines, we detected pre-diabetes in 4 subjects and diabetes in 1 subject, while all other subjects had normal FPG values. At 120 minutes, the correlations between the OGTT and cardiometabolic risk score (CMRS) were: r = 0.56 (p = 0.004) for glucose and r = 0.53 (p = 0.006) for insulin. At 120 minutes, the correlations between the OGTT and photoplethysmography index (PTGi) were: r = -0.56 (p = 0.003) for glucose and r = -0.41 (p = 0.04) for insulin. The CMRS, PTGi, and plethysmography total power index (PTGVLFi) differed significantly between the diabetes patients and healthy participants. The specificity and sensitivity for the CMRS, PTGi, and PTVLFi comparing the diabetes patients with healthy controls were high.

Conclusion

The TM-Oxi and SudoPath system shows promise as a valid, convenient, and non-invasive screening method for type 2 diabetes mellitus. The ANS function and CMR indicators measured by this system may be useful in guiding diabetes and cardiovascular health screening, treatment, and monitoring.

oxLDL induces injury and defenestration of human liver sinusoidal endothelial cells via LOX1

Non-alcoholic fatty liver disease is associated with hepatic microangiopathy and liver inflammation caused by type 2 diabetes mellitus. Oxidised LDL (oxLDL) is involved in proinflammatory and cytotoxic events in various microcirculatory systems. The lectin-like oxLDL receptor 1 (LOX1) plays a crucial role in oxLDL-induced pathological transformation. However, the underlying mechanism of oxLDL's effects on liver microcirculation disturbances remains unclear. In this study, we investigated the effects of oxLDL on LOX1 (OLR1) expression and function, as well as on the fenestration features of human liver sinusoidal endothelial cells (HLSECs) in vitro. Primary HLSECs were obtained and cultured. The cells were treated with various concentrations of oxLDL (25, 50, 100 and 200  μg/ml), and the cytotoxicity and expression of LOX1 were examined. Furthermore, LOX1 knockdown was performed using siRNA technology, and the changes in intracellular reactive oxygen species (ROS), NFκB, p65, (p65), endothelin 1 (ET1 (EDN1)), eNOS (NOS3) and caveolin 1 (CAV1) levels were measured. Cells were treated with 100  μg/ml oxLDL, and the fenestra morphology was visualised using scanning electron microscopy. oxLDL significantly increased LOX1 expression at both the mRNA and protein levels in HLSECs in a dose- and time-dependent manner. oxLDL stimulation increased ROS generation and NFκB activation, upregulated ET1 and caveolin 1 expression, downregulated eNOS expression and reduced the fenestra diameter and porosity. All of these oxLDL-mediated effects were inhibited after LOX1 knockdown. These results reveal a mechanism by which oxLDL stimulates the production of LOX1 through the ROS/NFκB signalling pathway and by which LOX1 mediates oxLDL-induced endothelial injury and the defenestration of HLSECs.

Vascular compliance in lean, obese, and diabetic children and adolescents: a cross-sectional study in a minority population

BACKGROUND

In adults, both obesity and type 2 diabetes mellitus (T2DM) are positively correlated with cardiovascular disease mortality and arterial stiffness. Several studies of adults have shown that both obesity and T2DM are independently associated with increased arterial stiffness. However, little is known about the relationship between arterial compliance and cardiovascular disease risk in children. We assessed whether large and small arterial compliance is impaired in obese and diabetic pubertal children.

METHODS

One hundred children of African-Caribbean ethnicity, aged 14-16 years, including 21 lean children (between the 25th and 75th percentile), 40 obese children (>95th percentile), and 39 children with T2DM diagnosed by American Diabetes Association criteria were studied. Arterial compliance of the large (C1) and small (C2) vessels was measured using radial arterial diastolic pulse wave contour analysis.

RESULTS

C1 did not differ significantly between lean, obese, and T2DM subjects. C2 was significantly greater in obese and T2DM subjects (10.9 ± 1 and 10.4 ± 0.7 ml/mm Hg × 100 ml, respectively) compared to lean subjects (7.8 ± 0.8 ml/mm Hg × 100 ml; p < 0.05). C2 was also significantly greater in T2DM subjects receiving antihypertensive drug therapy than in diabetic subjects not on antihypertensive treatment.

CONCLUSION

Increased compliance in diabetic and obese children compared to lean subjects could be secondary to premature maturation of the vascular system; whether this early maturation can translate into a subsequent rise in the incidence of cardiovascular events related to diabetes and obesity can only be determined by long-term follow-up of these patients.

Arterial stiffness, renal function and renal blood flow in patients with coronary artery disease, arterial hypertension and type 2 diabetes mellitus

Aim. To investigate the relationship between changes in indicators of arterial stiffness of various types of vessels, hemodynamic pulsatility, renal function and renal blood flow in patients with coronary artery disease (CAD) and arterial hypertension in the presence or absence of type 2 diabetes mellitus (T2DM). Materials and Methods. The study included 96 patients with CAD and arterial hypertension; among them, 54 subjects had T2DM and 42 did not. Сarbohydrate and lipid metabolism, renal function, stiffness of various types of arteries, parameters of hemodynamic pulsatility and renal blood flow were investigated. Results. Arterial stiffness of various types of vessels was increased in the T2DM group: carotid?femoral pulse wave velocity as a marker of aortic stiffness (a vessel of the elastic type) was increased by 16% (p

Does Vascular Elasticity Affect Arteriovenous Fistula Maturation?

The vasculopathy of ESRD affects both arteries and veins. The arteries develop arteriosclerosis, which is largely a disease of the media characterized by increased collagen content, calcification, and both hypertrophy and hyperplasia of vascular smooth muscle cells. Veins may exhibit increased width of the intimal and medial layers, and may develop neointimal hyperplasia and calcification. Successful fistula maturation depends upon dilatation and remodeling of the artery and vein, but the stiff and thickened vessels of ESRD patients may respond poorly to signals that promote these adaptations. There is intense interest in accurately predicting fistula maturation outcome and preventing maturation failure. However, definitive criteria for preoperative testing of vessel elasticity have not yet been established. Tests that are adopted for widespread clinical use will need to be easy to apply - a standard that many of these tests may not meet. Finally, effective treatments are needed that prevent or reduce the stiffness of vessels. In conclusion, although there are many promising developments in this emerging field, effective methods of predicting fistula maturation outcome and preventing maturation failure remain to be established.

Amplification of AngII-dependent cell contraction by glyoxal: implication of cell mechanical properties and actomyosin activity

Glyoxal (GO), a highly reactive metabolite of glucose, is associated with diabetic vascular complications via the formation of advanced glycation end-products. Considering its ability to react with proteins' amino acids and its crosslinking potential, we suggest that GO affects cellular mechanical functions such as contractility. Therefore, we tested the effects of GO on cellular contractile response following AngII stimulation of human embryonic kidney cells over-expressing the AT1 receptor (HEK 293 AT1aR). Prior to cell stimulation with AngII, cells exposed to GO exhibited carboxymethyllysine-adduct formation and an increase in cellular stiffness, which could be prevented by pre-treatment with aminoguanidine. The time-dependent cellular contractile response to AngII was measured by monitoring cell membrane displacement by atomic force atomic force microscopy (AFM) and by quantifying myosin light chain phosphorylation (p-MLC) via immunoblotting. Interestingly, short-term GO exposure increased by 2.6 times the amplitude of cell contraction induced by AngII and this was also associated with a sustained rise in p-MLC. This increased response to AngII induced by GO appears to be linked to its glycation potential, as aminoguanidine pre-treatment prevented this increased cellular mechanical response. Our results also suggest that GO could have an impact on ROCK activity, as ROCK inhibition with Y-27632 blocked the enhanced contractile response (p = 0.011) measured under GO conditions. Together, these results indicate that GO enhances the cellular response to AngII and modifies cellular mechanical properties via a mechanism that relies on its glycation potential and on the activation of the ROCK-dependent pathway.

Investigation of endothelial dysfunction and arterial stiffness in children with type 1 diabetes mellitus and the association with diastolic dysfunction

OBJECTIVE

The objective of this study is to investigate endothelial dysfunction (ED) and arterial stiffness (AS) and determine the association with diastolic dysfunction in children with type 1 diabetes mellitus (DM).

METHODS

A total of 42 patients without diabetic complications (mean age: 13.21 years) and 40 healthy (mean age: 13.07 years) children were included in this study. AS was assessed with ascending aorta M-mode measurements, diastolic dysfunction with pulsed wave (PW) Doppler and tissue Doppler echocardiography measurements and flow-mediated dilatation (FMD) and carotid intima-media thickness (CIMT) with high-resolution ultrasonography.

RESULTS

Results of diabetic group and healthy children were compared. In diabetic group, aortic strain (8.40 ± 2.98, 20.12 ± 5.04; p < 0.001), aortic distensibility (7.36 ± 2.92, 16.59 ± 4.25; p < 0.001) and FMD% (7.70 ± 2.83, 11.33 ± 2.85; p < 0.001) were found decreased, and CIMT (0.52 ± 0.09 mm, 0.47 ± 0.08 mm; p < 0.05) was found increased. Additionally, left ventricular lateral segment and right ventricular free-wall isovolumic relaxation time (IVRT) and myocardial performance index (MPI) were found increased. Correlation analyses demonstrated a negative correlation between FMD and IVRT and MPI.

CONCLUSIONS

ED and AS were found in type 1 DM patients without diabetic complications. Additionally, correlation was shown between increased AS and ED and right and left ventricular diastolic dysfunctions.

Improvement of arterial wall characteristics by the low-dose fluvastatin and valsartan combination in type 1 diabetes mellitus patients

We tested whether short-term, low-dose treatment with the fluvastatin and valsartan combination could improve impaired arterial wall characteristics in type 1 diabetes mellitus patients. A total of 44 type 1 diabetes mellitus patients were randomised into the treatment group [n = 22; received a low-dose combination of fluvastatin (10 mg daily) and valsartan (20 mg daily)] and the control group (n = 22; received placebo), both for 30 days. Brachial artery flow-mediated dilation (FMD), pulse wave velocity (PWV) and carotid artery β-stiffness were measured. Significant improvements in FMD (+73.2%), PWV (-7.5%) and β-stiffness (-10.0%) were achieved after 1-month treatment compared to the control group (all p values < 0.001). Three months after therapy discontinuation, important residual improvement in measured parameters was still present. No changes in lipids and blood pressure accompanied the beneficial improvements. We conclude that relatively simple intervention (low-dose, short-term fluvastatin/valsartan combination) produces substantial, long-term improvement of arterial wall characteristics in type 1 diabetes mellitus patients.

Impact of diabetes mellitus on arterial stiffness in a representative sample of an urban Brazilian population

BACKGROUND

Independent of other cardiovascular (CV) risk factors, increased arterial stiffness has been established as a predictor of morbidity and mortality. The main aim of this study was to investigate the impact of diabetes on arterial stiffness in a representative sample of an urban Brazilian population plus Amerindians.

METHODS

A total of 1,415 individuals from the general population were randomly selected plus 588 Amerindians from a native community in Brazil. In addition, a sub-sample of 380 individuals from the general population had 5-year follow-up data. Pulse wave velocity (PWV) was measured with a non-invasive automatic device (Complior, Colson; Garges les Gonesses, France) and increased arterial stiffness was defined as PWV ≥ 12 m/s.

RESULTS

In the overall group, diabetic individuals had higher frequencies of increased arterial stiffness and hypertension. They also had higher values of PWV, body mass index, total cholesterol, triglycerides, systolic and diastolic blood pressures compared to non-diabetic individuals (p < 0.01). In an analysis stratified by hypertension, PWV values and increased arterial stiffness frequency were higher in diabetic individuals in both groups (hypertensive and non-hypertensive) (p < 0.05). Furthermore, higher risk for increased arterial stiffness was observed in the diabetic individuals from the overall group (OR = 2.27; CI = 1.47-3.52, p < 0.001) and from the hypertensive group (OR = 2.70; CI = 1.58-4.75, p < 0.001), adjusted for covariates. Regarding the ethnic stratification, diabetic individuals from Amerindian, White, and Mulatto (mixed-race) groups had higher PWV values and a greater frequency of increased arterial stiffness compared to non-diabetic individuals. Both diabetic and non-diabetic individuals had higher PWV values after 5 years. There was no significant difference in the 5-year PWV progression in diabetic compared to non-diabetic individuals.

CONCLUSIONS

These results confirm, in a sample of Brazilian population, that the presence of diabetes is associated with increased arterial stiffness and it may contribute in part to increased cardiovascular risk in diabetic patients.

Association of arterial stiffness with single nucleotide polymorphism rs1333049 and metabolic risk factors

Background

Increased arterial stiffness is a cardiovascular outcome of metabolic syndrome (MetS). The chromosome 9p21 locus has been identified as a major locus for risk of coronary artery disease (CAD). The single nucleotide polymorphism (SNP), rs1333049 on chromosome 9p21.3 has been strongly associated with CAD and myocardial infarction. Increased arterial stiffness could be the link between the 9p21 polymorphism and increased cardiovascular risk. Since the impact of a genetic polymorphism on arterial stiffness especially in Asian populations has not been well defined, we aimed to investigate the association of arterial stiffness with rs 1333049 variant on chromosome 9p21.3 in Thai subjects with and without MetS risk factors.

Methods

A total of 208 Thai subjects, aged 35–75 years, 135 with and 73 without MetS, according to IDF and NCEP-ATPIII criteria, were included in this study. Aortic-femoral pulse wave velocity (afPWV), brachial-ankle pulse wave velocity (baPWV) and aortic ankle pulse wave velocity (aaPWV) were measured and used as markers of arterial stiffness. The chromosome 9p21.3 locus, represented by the rs 1333049 variant and blood biochemistry were evaluated.

Results

Arterial stiffness was elevated in subjects with MetS when compared with nonMetS subjects. PWV, especially afPWV increased progressively with increasing number of MetS risk factors (r = 0.322, P <0.001). We also found that the frequency distribution of the rs1333049 genotypes is significantly associated with the afPWV (P <0.05). In multivariate analyses, there was an association between homozygous C allele and afPWV (Odds ratio (OR), 8.16; 95% confidence interval (CI), 1.91 to 34.90; P = 0.005), while the GC genotype was not related to afPWV (OR, 1.79; 95% CI, 0.84 to 3.77; P = 0.129) when compared with the GG genotype.

Conclusions

Our findings demonstrate for the first time that arterial stiffness is associated with genetic polymorphism in 9p21 and metabolic risk factors in a Thai population.

Arterial compliance is increased in children with type 2 diabetes compared with normal weight peers but not obese peers

BACKGROUND

We reported that obesity was associated with increased arterial compliance in children, possibly due to accelerated vascular maturation. Here, we explored the additional burden of type 2 diabetes (T2DM) on vascular function in children.

METHODS

Fifty normal weight [body mass index (BMI) 25-75%], 58 obese (BMI ≥ 95%), and 34 children with T2DM diagnosed by American Diabetes Association (ADA) criteria ages 10-18 yr were studied. Large and small artery elasticity (LAEI and SAEI, respectively) were measured by diastolic pulse-wave contour analysis.

RESULTS

SAEI was 27% higher in children with T2DM compared to normal weight children (p = 0.005). Mean LAEI for those with T2DM not different from either group. In the group with T2DM, both SAEI and LAEI increased with age up to 16 yr, but declined thereafter. The strongest multivariable model predicting SAEI in children with T2DM combined lean mass, systolic blood pressure (SBP), and glucose (r2  = 0.59); for predicting LAEI, the strongest model included height, SBP, and low-density lipid-cholesterol (r2  = 0.61).

CONCLUSION

The lower arterial compliance in older adolescents with T2DM compared to that of their peers without diabetes may indicate a premature maturation of the vascular system; however, follow-up will clarify whether these vascular changes portend an early increase in diabetes-associated cardiovascular disease risk.

Decreased expression of γ-carboxylase in diabetes-associated arterial stiffness: impact on matrix Gla protein

AIMS

Arterial stiffness is accelerated in type 1 diabetic patients. Medial artery calcification (MAC) contributes to the development of arterial stiffness. Vitamin K oxidoreductase (VKOR) reduces the vitamin K required by γ-carboxylase to activate matrix γ-carboxyglutamic acid (Gla) protein (MGP), an inhibitor of vascular calcification. This study aimed to evaluate the hypothesis that diabetes reduces the γ-carboxylation of MGP in the aortic wall, leading to increased vascular calcification, and the role of γ-carboxylase and VKOR in this γ-carboxylation deficit.

METHODS AND RESULTS

Type 1 diabetes was induced in male Wistar rats with a single ip injection of streptozotocin. Augmentation of arterial stiffness in diabetic rats was shown by a 44% increase in aortic pulse wave velocity. Aortic and femoral calcification were increased by 26 and 56%, respectively. γ-Carboxylated MGP (cMGP, active) was reduced by 36% and the aortic expression of γ-carboxylase was reduced by 58%. Expression of γ-carboxylase correlated with cMGP (r= 0.59) and aortic calcification (r = -0.57). VKOR aortic expression and activity were not modified by diabetes. Vitamin K plasma concentrations were increased by 191% in diabetic rats. In ex vivo experiments with aortic rings, vitamin K supplementation prevented the glucose-induced decrease in γ-carboxylase expression.

CONCLUSION

Our results suggest that reduced cMGP, through an impaired expression of γ-carboxylase, is involved in the early development of MAC in diabetes, and therefore, in the acceleration of arterial stiffness. A defect in vitamin K uptake by target cells could also be involved.

Endothelial barrier disruption and recovery is controlled by substrate stiffness

Circulating barrier disruptive agonists bind specific cell membrane receptors and trigger signal transduction pathways leading to the activation of cell contractility and endothelial cell (EC) permeability. Although all cells in tissues including vascular EC are surrounded by compliant extracellular matrix, the impact of matrix stiffness on agonist-induced signaling, cytoskeletal remodeling and EC barrier regulation is not well understood. This study examined agonist-induced cytoskeletal and signaling changes associated with EC barrier disruption and recovery using pulmonary EC grown on compliant substrates of physiologically relevant (8.6 kPa) stiffness, very low (0.55 kPa) and very high (42 kPa) stiffness. Human pulmonary microvascular and macrovascular EC grown on 0.55 kPa substrate contained a few actin stress fibers, while stress fiber amount increased with increasing matrix stiffness. Thrombin-induced stress fiber formation was maximal in EC grown on 42 kPa substrate, diminished on 8.6 kPa substrate, and was minimal on 0.55 kPa substrate. These effects were linked to a stiffness-dependent increase in thrombin-induced phosphorylation of the Rho kinase target, myosin light chain phosphatase (MYPT1), and regulatory myosin light chains (MLC). Surprisingly, EC barrier recovery and activation of Rac GTPase-dependent barrier protective signaling reached maximal levels in EC grown on 8.6 kPa, but not on 0.55 kPa substrate. In conclusion, these data show a critical role of extracellular matrix stiffness in the regulation of the Rac/Rho signaling balance during onset and resolution of agonist-induced EC permeability. The optimal conditions for the Rho/Rac signaling switch, which provides an effective and reversible EC cytoskeletal and permeability response to agonist, are reached in cells grown on the matrix of physiologically relevant stiffness.

Increased nitric oxide activity compensates for increased oxidative stress to maintain endothelial function in rat aorta in early type 1 diabetes

Hyperglycaemia and oxidative stress are known to acutely cause endothelial dysfunction in vitro, but in the initial stages of diabetes, endothelium-dependent relaxation is preserved. The aim of this study was to investigate how endothelium-dependent relaxation is maintained in the early stages of type 1 diabetes. Diabetes was induced in Sprague-Dawley rats with a single injection of streptozotocin (48 mg/kg, i.v.), and after 6 weeks, endothelium-dependent and endothelium-independent relaxations were examined in the thoracic aorta in vitro. Lucigenin-enhanced chemiluminescence was used to measure superoxide generation from the aorta. Diabetes increased superoxide generation by the aorta (2,180 ± 363 vs 986 ± 163 AU/mg dry tissue weight). Acetylcholine (ACh)-induced relaxation was similar in aortae from control (pEC(50) 7.36 ± 0.09, R (max) 95 ± 3 %) and diabetic rats (pEC(50) 7.33 ± 0.10, R (max) 88 ± 5 %). The ACh-induced relaxation was abolished by the combined presence of the nitric oxide synthase inhibitor N-nitro-L-arginine (L-NNA, 100 μM) and an inhibitor of soluble guanylate cyclase, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 10 μM) in control rats, but under the same conditions, the diabetic aortic rings showed significant relaxation to ACh (pEC(50) 6.75 ± 0.15, R (max) 25 ± 4 %, p < 0.05). In diabetic aortae, the addition of haemoglobin, which inactivates nitric oxide, to L-NNA + ODQ abolished the response to ACh. The addition of the potassium channel blockers, apamin and TRAM-34, to L-NNA + ODQ also abolished the relaxation response to ACh. Diabetes significantly elevated plasma total nitrite/nitrate and increased expression of endothelial nitric oxide synthase (eNOS) and calmodulin in aortae. These data indicate that after 6 weeks of diabetes, despite increased oxidant stress, endothelium-dependent relaxation is maintained due to the increased eNOS expression resulting in increased NO synthesis. In diabetic arteries, NO acts both through and independently of cGMP pathways to cause relaxation.

Hemoglobin A1c levels and aortic arterial stiffness: the Cardiometabolic Risk in Chinese (CRC) study

OBJECTIVE

The American Diabetes Association (ADA) recently published new clinical guidelines in which hemoglobin A1c (HbA1c) was recommended as a diagnostic test for diabetes. The present study was to investigate the association between HbA1c and cardiovascular risk, and compare the associations with fasting glucose and 2-hour oral glucose tolerance test (2 h OGTT).

RESEARCH DESIGN AND METHODS

The study samples are from a community-based health examination survey in central China. Carotid-to-femoral pulse wave velocity (cfPWV) and HbA1c were measured in 5,098 men and women.

RESULTS

After adjustment for age, sex, and BMI, the levels of HbA1c were significantly associated with an increasing trend of cfPWV in a dose-dependent fashion (P for trend <0.0001). The associations remained significant after further adjustment for blood pressure, heart rate, and lipids (P = 0.004), and the difference in cfPWV between the highest and the lowest quintiles of HbA1c was 0.31 m/s. Fasting glucose and 2 h OGTT were not associated with cfPWV in the multivariate analyses. HbA1c showed additive effects with fasting glucose or 2 h OGTT on cfPWV. In addition, age and blood pressure significantly modified the associations between HbA1c and cfPWV (P for interactions <0.0001 for age; and  = 0.019 for blood pressure). The associations were stronger in subjects who were older (≥60 y; P for trend = 0.004) and had higher blood pressure (≥120 [systolic blood pressure]/80 mmHg [diastolic blood pressure]; P for trend = 0.028) than those who were younger and had lower blood pressure (P for trend >0.05).

CONCLUSIONS

HbA1c was related to high cfPWV, independent of conventional cardiovascular risk factors. Senior age and high blood pressure might amplify the adverse effects of HbA1c on cardiovascular risk.

[Relationships between baroreflex gain and pulsatile stress in type 1 diabetic patients]

AIM OF THE STUDY

Cardiovascular autonomic neuropathy (CAN) and early arterial stiffness are frequent complications in type 1 diabetes. The aim of our work is to study the relationships between CAN (estimated by baroreflex gain calculation) and arterial stiffness (estimated by pulsatile stress) in type 1 diabetic patients.

PATIENTS AND METHODS

In a cross-sectional study, we calculated baroreflex gain and pulsatile stress in 167 type 1 diabetic patients and 160 matched non-diabetic subjects whose blood pressure was continuously monitored with a Finapres(®) device in a postural test (squatting test). The baroreflex gain was calculated by plotting the pulse intervals (R-R) against systolic blood pressure values during the transition phase from squatting to standing. Pulsatile stress was estimated by the pulse pressure×heart rate product. In a longitudinal study, the baroreflex gain and pulsatile stress were calculated before and after a mean follow-up of 79±33 months in type 1 diabetic patients.

RESULTS

Cross-sectional data showed a decrease in baroreflex gain and an increase in pulsatile stress in type 1 diabetic patients versus the matched non-diabetic subjects. A significant correlation between the baroreflex gain and pulsatile stress was present. Type 1 diabetic patients with lower baroreflex gain had a higher value of pulsatile stress when compared to those with higher baroreflex gain. During follow-up, a significant reduction in baroreflex gain (but without significantly increased pulsatile stress) was observed. A univariate analysis showed that the decrease of the baroreflex gain is not correlated with the time interval between the two tests, neither type 1 diabetes duration nor mean glycated hemoglobin values, but significantly with the pulsatile stress increase.

CONCLUSION

In type 1 diabetic patients, the baroreflex gain is decreased and the pulsatile stress is increased when these markers are compared to age-matched non-diabetic subjects. There is a relationship between indices of CAN and arterial stiffness. Nevertheless, the baroreflex gain (marker of CAN) is impaired earlier than the pulsatile stress in this type 1 diabetic population with inadequate glycaemic control.

Correlation between serum lactadherin and pulse wave velocity and cardiovascular risk factors in elderly patients with type 2 diabetes mellitus

AIMS

This study was carried out with the purpose of investigating the association between serum lactadherin, monocyte chemoattractant protein 1 (MCP-1), tumor necrosis factor alpha (TNFα) and carotid-femoral pulse wave velocity (PWV) in elderly patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 105 subjects including 27 T2DM patients without vascular complications (DM), 28 T2DM patients with vascular complications (DC), 25 elderly healthy volunteers (older) and 25 younger healthy volunteers (younger) were recruited into the study. Carotid-femoral PWV was measured using an automatic device. Serum lactadherin, MCP-1 and TNFα were determined by enzyme linked immunosorbent assay.

RESULTS

PWV and lactadherin, MCP-1 and TNFα were significantly higher in DM and DC groups than those of older and younger groups. PWV and lactadherin were higher in older group than those of younger group. Moreover, lactadherin was significantly correlated with MCP-1, TNFα, PWV, HbA1c and 2 h postprandial blood glucose (P2hBG) (P<0.05). In multivariate regression analysis, the independent determinants of lactadherin were HbA1c, P2hBG and age (P<0.05).

CONCLUSIONS

These findings underscore that lactadherin is correlated with poor blood glucose control and diabetic vascular complications.

Circulating endothelial progenitor cells and large artery structure and function in young subjects with uncomplicated type 1 diabetes

Background

Carotid intima-media thickness (IMT), indices of large artery stiffness and measures of endothelium function may be used as markers of early atherosclerosis in type 1 diabetes mellitus (T1DM). The aim of the present study was to compare the indices of large artery structure and function as well as endothelial function and regenerating capacity between adolescents with T1DM and healthy control of similar age. In addition, the associations of different vascular measures with endothelial progenitor cells (EPCs), glyco-metabolic control and serum levels of advanced glycation endproducts (AGEs), soluble receptors for AGEs (sRAGE) and adiponectin were evaluated.

Methods

Sixteen uncomplicated young T1DM patients (mean age 18 ± 2 years, history of disease 11 ± 5 years, HbA1c 7.7 ± 1.1%) and 26 controls (mean age 19 ± 2 years) were studied. A radiofrequency-based ultrasound system (Esaote MyLab 70) was used to measure carotid IMT and wave speed (WS, index of local stiffness), applanation tonometry (PulsePen) was applied to obtain central pulse pressure (PP) and augmentation index (AIx), and carotid-femoral pulse wave velocity (PWV, Complior) was used as index of aortic stiffness. Peripheral endothelium-dependent vasodilation was determined as reactive hyperemia index (RHI, EndoPAT). Circulating EPCs, glycometabolic profile, AGEs (autofluorescence method), sRAGE and adiponectin were also measured.

Results

After adjusting for age, sex and blood pressure, T1DM adolescents had significantly higher carotid IMT (456 ± 7 vs. 395 ± 63 μm, p < 0.005), carotid WS (p < 0.005), PWV (p = 0.01), AIx (p < 0.0001) and central PP (p < 0.01) and lower EPCs (p = 0.02) as compared to controls. RHI was reduced only in diabetic patients with HbA1c ≥7.5% (p < 0.05). In the overall population, EPCs were an independent determinant of carotid IMT (together with adiponectin), while fasting plasma glucose was an independent determinant of carotid WS, AIx and central PP.

Conclusions

Our findings suggest that young subjects with relatively long-lasting T1DM have a generalized preclinical involvement of large artery structure and function, as well as a blunted endothelium regenerating capacity. Hyperglycemia and suboptimal chronic glycemic control seem to deteriorate the functional arterial characteristics, such as large arteries stiffness, wave reflection and peripheral endothelium-dependent vasodilation, whereas an impaired endothelium regenerating capacity and adiponectin levels seem to influence arterial structure.

Pharmacological evaluation of insulin mimetic novel suppressors of PEPCK gene transcription from Paeoniae Rubra Radix

ETHNOPHARMACOLOGICAL RELEVANCE

Paeoniae Rubra Radix (root of Paeonia lactiflora) has been frequently employed in Traditional Chinese Medicine (TCM) as and anti-diabetic therapy to enhance blood circulation and dissipate stasis.

AIM OF THE STUDY

Previously, we identified a novel hypoglycemic action of a crude extract from Paeoniae Rubra Radix, which also suppressed phosphoenolpyruvate carboxykinase (PEPCK) gene transcription. Therefore, the current investigation intended to elucidate potential active bio-constituents of this herb and mechanisms of action.

MATERIALS AND METHODS

Glucocorticoid receptor (GR) nuclear localization, the PEPCK messenger (m)RNA level, pregnane X receptor (PXR) mRNA expression, cAMP-responsive element-binding protein (CREB) serine phosphorylation and DNA binding were evaluated in dexamethasone (Dex) and 8-bromo-cAMP (CA)-stimulated H4IIE cells, while efficacy of agents was assessed in a stable cell line containing a green fluorescent protein (GFP) reporter driven by the PEPCK promoter. HPLC profiling, colorimetric assays, and NMR analysis were employed for chemical characterization purpose.

RESULTS

An extract of Paeoniae Rubra Radix lacking the insulin mimetic compound, 1,2,3,4,6-penta-O-galloyl-beta-d-glucose (PGG), and termed the non-PGG fraction (NPF), consisting of tannin polymers, suppressed PEPCK expression in the presence of an insulin receptor antagonist (HNMPA-AM(3)), suggesting the action of this fraction is independent of the insulin receptor. Furthermore, Dex-stimulated GR nuclear localization and transactivation were prevented by the NPF. Similarly, CA-stimulated CREB serine phosphorylation and DNA binding were also inhibited by the NPF in H4IIE cells. Hence NPF antagonizes both signaling pathways that induce PEPCK gene transcription.

CONCLUSION

In conclusion, the current study proposes that the potent suppressive activity on PEPCK gene transcription observed with Paeoniae Rubra Radix extract, can be attributed to at least two distinct components, namely PGG and NPF.

Macrovascular angiopathy in children and adolescents with type 1 diabetes

Diabetes represents one of the most common diseases globally. Worryingly, the worldwide incidence of type 1 diabetes (T1D) is rising by 3% per year. Despite the rapid increase in diabetes incidence, recent advances in diabetes treatment have been successful in decreasing morbidity and mortality from diabetes-related retinopathy, nephropathy, and neuropathy. In contrast, there is clear evidence for the lack of improvement in mortality for cardiovascular diseases (CVDs). This emphasizes the importance of focusing childhood diabetes care strategies for the prevention of CVD in adulthood. Furthermore, although most work on diabetes and macrovascular disease relates to type 2 diabetes, it has been shown that the age-adjusted relative risk of CVD in T1D far exceeds that in type 2 diabetes. As T1D appears predominantly during childhood, those with T1D are at greater risk for coronary events early in life and require lifelong medical attention. Because of the important health effects of CVDs in children and adolescents with T1D, patients, family members, and care providers should understand the interaction of T1D and cardiovascular risk. In addition, optimal cardiac care for the patient with diabetes should focus on aggressive management of traditional cardiovascular risk factors to optimize those well-recognized as well as new specific risk factors which are becoming available. Therefore, a complete characterization of the molecular mechanisms involved in the development and progression of macrovascular angiopathy is needed. Furthermore, as vascular abnormalities begin as early as in childhood, potentially modifiable risk factors should be identified at an early stage of vascular disease development.

Characterizing the elastic properties of tissues

The quality of life of ageing populations is increasingly determined by age-related changes to the mechanical properties of numerous biological tissues. Degradation and mechanical failure of these tissues has a profound effect on human morbidity and mortality. Soft tissues have complex and intricate structures and, similar to engineering materials, their mechanical properties are controlled by their microstructure. Thus age-relate changes in mechanical behavior are determined by changes in the properties and relative quantities of microstructural tissue components. This review focuses on the cardiovascular system; it discusses the techniques used both in vivo and ex vivo to determine the age-related changes in the mechanical properties of arteries.

The association of brachial-ankle pulse wave velocity with 30-minute post-challenge plasma glucose levels in korean adults with no history of type 2 diabetes

Background

Acute postprandial hyperglycemia is an important affector for atherosclerosis in subjects with glucose intolerance. We analyzed the relationship of brachial-ankle pulse wave velocity (baPWV) with fasting and post-challenge plasma glucose levels according to different time points during oral glucose tolerance test (OGTT).

Methods

In 663 subjects with fasting hyperglycemia, 75 g OGTT were performed to confirm the glucose tolerant status, and fasting, post-challenge 30-minute and 120-minute glucose levels were measured. Anthropometric measurements were done, and fasting lipid profiles were measured. baPWV were measured in all subjects and the relationship between fasting, 30- and 120-minute post-challenge glucose levels and baPWV were analyzed.

Results

Among the participants, 62.9% were prediabetes and 31.7% were diabetes. Mean baPWV value was significantly higher in subjects with diabetes compared with prediabetes group. In bivariate correlation analyses, age, blood pressure, total cholesterol, low density lipoprotein cholesterol, 30-minute and 120-minute post-challenge glucose levels showed significant positive correlation with baPWV value. In multiple regression analysis, 30-minute post-challenge glucose level was a weak but significant determinant for mean baPWV value even after adjustment for other confounding variables.

Conclusions

Postprandial hyperglycemia, especially 30-minute glucose levels showed significant correlation with baPWV in subjects with fasting hyperglycemia. These results can imply the deleterious effect of acute hyperglycemic excursion on arterial stiffness in subjects with glucose intolerance.

Mean arterial pressure nonlinearity in an elastic circulatory system subjected to different hematocrits

The level of hematocrit (Hct) is known to affect mean arterial pressure (MAP) by influencing blood viscosity. In the healthy population, an increase in Hct (and corresponding increase in viscosity) tends to raise MAP. However, data from a clinical study of type 2 diabetic patients indicate that this relationship is not universal. Instead, individuals in the lower levels of Hct range display a decrease in MAP for a given rise in Hct. After reaching a minimum, this trend is reversed, so that further increases in Hct lead to increases in MAP. We hypothesize that this anomalous behavior occurs due to changes in the circulatory autoregulation mechanism. To substantiate this hypothesis, we develop a physically based mathematical model that incorporates autoregulation mechanisms. Our model replicates the anomalous U-shaped relationship between MAP and Hct found in diabetic patients in the same range of Hct variability.

Changes in pulse pressure, heart rate and the pulse pressure x heart rate product during squatting in Type 1 diabetes according to age

AIMS

We assessed changes in pulse pressure and heart rate during a squatting test, as indirect markers of arterial stiffness and cardiovascular autonomic neuropathy, respectively, according to age and sex in patients with Type 1 diabetes mellitus.

METHODS

We evaluated 160 diabetic patients, divided into four groups of 20 men and 20 women according to age (G1, 20-30 years old; G2, 31-40 years old; G3, 41-50 years old; and G4, 51-60 years old), and 160 non-diabetic matched control subjects. Each subject underwent a 3 min posture test (standing-squatting-standing) with continuous measurement of arterial blood pressure and heart rate by a Finapres device. Overall values throughout the test, baseline levels in initial standing position and squatting-induced changes in pulse pressure, heart rate and the pulse pressure x heart rate product were compared between diabetic patients and healthy control subjects.

RESULTS

In the standing position, a greater increase in pulse pressure and lower reduction in heart rate with age led to a significantly higher pulse pressure x heart rate product in diabetic patients compared with control subjects. In the squatting position, a more marked pulse pressure increase in the absence of appropriate reduction in heart rate resulted in a greater rise in the pulse pressure x heart rate product in diabetic patients than in healthy subjects. No major differences were noted between the sexes, with the exception of a stronger relationship between pulse pressure and age in the female population with diabetes. Squatting-derived indices of cardiovascular autonomic neuropathy were also noted with increasing age in diabetic patients.

CONCLUSIONS

The marked increase in the pulse pressure x heart rate product ('pulsatile stress') according to age, combined with cardiovascular autonomic neuropathy, may contribute to the higher cardiovascular risk of patients with Type 1 diabetes.

The effect of smoking on arterial stiffness

A systematic literature review was conducted using PubMed, Embase and the Cochrane Library to determine the effect of acute, chronic and passive smoking on arterial stiffness and to determine whether these effects are reversible after smoking cessation. A total of 39 relevant studies were identified and included. Acute smoking was found to cause an acute increase in arterial stiffness. Similarly, passive smoking increased arterial stiffness acutely and chronically. The majority of studies identified chronic smoking as a risk factor for increasing arterial stiffness. However, some studies found no statistical difference in arterial stiffness between nonsmokers and long-term smokers, although chronic smoking seems to sensitize the arterial response to acute smoking. In addition, whether arterial stiffness is reversed after smoking cessation and the timeline in which this may occur could not be determined from the identified literature. The effect of smoking discontinuation on arterial stiffness remains to be established by prospective smoking cessation trials.

Relationship between upper limb peripheral artery stiffness using the radial artery and atherosclerotic parameters

PURPOSE

A new method has been developed for evaluating arterial stiffness using transcutaneous and high-frequency ultrasound. There may be a difference in the clinical significance of peripheral arteries, such as the radial artery (a muscular property), and other medium/large-sized arteries (an elastic property). The aim of this study was to determine the relationship between upper limb peripheral arterial stiffness (ULPAS) using the new method for the radial artery and atherosclerotic parameters in comparison with carotid intima-media thickness (IMT) and cardio-ankle vascular index (CAVI) in a healthy population and a diseased population with hypertension (HT) and diabetes mellitus (DM).

METHODS

Forty-four apparently healthy individuals (mean age = 26.3 years, men/women = 14/30), 45 patients with drug-treated HT (mean age = 55.3 years, men/women = 17/28), and 37 patients with drug-treated DM (mean age = 55.2 years, men/women = 21/16) were investigated. Body mass index, systolic blood pressure (SBP), diastolic blood pressure (DBP), CAVI, IMT, ultrasonographically measured ULPAS, blood lipid/glucose-related parameters, and C-reactive protein (CRP) were all determined.

RESULTS

Among the healthy subjects, ULPAS showed a significantly positive correlation with SBP and CRP. ULPAS showed a different correlation pattern with atherosclerotic parameters from that of IMT and CAVI. The HT subjects had significantly higher ULPAS levels than those with DM. In this diseased population, ULPAS showed a significant positive correlation with SBP and DBP, as well as a significant negative correlation with glucose.

CONCLUSION

These results suggest that ULPAS may provide new information in association with some atherosclerotic conditions as a unique index different from IMT and CAVI.

Pulse pressure and cardiovascular autonomic neuropathy according to duration of type 1 diabetes

BACKGROUND

To evaluate changes in pulse pressure (PP) and markers of cardiovascular autonomic neuropathy (CAN) according to duration of type 1 diabetes mellitus (T1DM).

METHODS

This cross-sectional controlled study evaluated 159 diabetic patients during a 3-min posture test (standing-squatting-standing) with continuous measurement of systolic (SBP), diastolic (DBP) and mean (MBP) blood pressure by a Finapres device. Arterial stiffness was indirectly assessed by PP and the slope of PP as a function of MBP calculated during the whole 3-min test. CAN was assessed by the expiration/inspiration pulse interval ratio (E/I R-R ratio) during deep breathing and by three indices measured during the squatting test. Patients were divided into four groups according to diabetes duration (<10 years, 11-20 years, 21-30 years and > 30 years from group 1 to group 4, respectively) and compared with age-matched non-diabetic subjects.

RESULTS

PP progressively increased (p < 0.0001) and PP/MBP decreased (p < 0.0005) according to T1DM duration, whereas these parameters remained almost unchanged in age-matched control subjects. E/I ratio (p < 0.0001) and baroreflex gain (p < 0.0005) progressively decreased with T1DM duration. The parasympathetic index (squatting test vagal ratio-SqTv) significantly increased (p < 0.0001), whereas the sympathetic index (squatting test sympathetic ratio-SqTs) only tended to decrease (p = 0.12) according to diabetes duration. No such changes in CAN indices were observed in the non-diabetic population.

CONCLUSIONS

PP increased according to T1DM duration in an age range where PP remained almost stable in controls, in agreement with accelerated arterial stiffening due to chronic hyperglycaemia. The baroreflex gain decreased and other indices of CAN also deteriorated with diabetes duration, more so indices reflecting parasympathetic rather than sympathetic dysfunction.