Association of Oxidative Stress Markers with Vascular Stiffness Parameters in Patients with Diabetic Neuropathy

Introduction: One of the most common chronic complications of diabetes mellitus is diabetic neuropathy. The aim of the study was to elucidate the association between selected markers of oxidative stress and markers of vascular stiffness and to contribute to the understanding of the pathophysiological links between oxidative stress and micro- and macrovascular complications of diabetes. Methods: We enrolled patients with type 2 DM (n = 49), with moderate to severe diabetic polyneuropathy of lower extremities, and a control group without microvascular complications (n = 29). The neuropathy group received alpha-lipoic acid infusion therapy. Sampling was performed before and after treatment to determine the level of oxidative markers (advanced glycation end-products—AGEs, glycation products of AOPP proteins, MDA malondialdehyde and oxidized LDL), parameters of metabolic control and parameters of vascular wall stiffness were measured by sphygmomanometry. Results: After the administration of alpha-lipoic acid, we demonstrated a significant reduction in the level of three selected oxidation markers (AOPP: p < 0.001, AGE: p < 0.001, oxLDL: p < 0.05). In contrast, the level of MDA did not change significantly (p = 0.83). Throughout the group, oxLDL was significantly correlated with central BP (SBP and DBP in the aorta, p < 0.05 and <0.01) and with the augmentation index (AiX/75 bpm, p < 0.01). AOPP significantly correlated with systolic BP in the aorta (p < 0.05). We did not find significant associations in the remaining oxidation markers. Conclusion: In our study, we demonstrated a reduction in the level of oxidative markers after alpha-lipoic acid administration and also an association between markers of oxidative damage to lipids and proteins (oxLDL and AOPP) and some parameters of vascular stiffness.

Impact of acute dynamic exercise on vascular stiffness in the retinal arteriole in healthy subjects

Acute exercise can improve vascular stiffness in the conduit artery, but its effect on the retinal arterioles is unknown. The present study investigated the effects of acute dynamic exercise on retinal vascular stiffness. In experiment 1, we measured the cardio-ankle vascular index (CAVI), carotid artery intima-media thickness (carotid IMT), and retinal blood velocity by laser speckle flowgraphy in 28 healthy old and 28 young men (69 ± 3 and 23 ± 3 years, respectively). Pulse waveform variables, which were used as an index of retinal vascular stiffness, were assessed by retinal blood flow velocity profile analysis. In experiment 2, 18 healthy old and 18 young men (69 ± 3 and 23 ± 3 years, respectively) underwent assessment of pulse waveform variables after a 30-min bout of moderate cycling exercise at an intensity of 60% heart rate reserve. There was a significant difference in the baseline pulse waveform variables between the old and young groups. Pulse waveform variables in the retinal arteriole did not significantly change after acute dynamic exercise, whereas CAVI significantly decreased. These findings suggest that retinal vascular stiffness does not change by acute exercise. The effect of exercise on vascular stiffness in the retinal arterioles might be different from that in the conduit artery.

Cystamine reduces vascular stiffness in Western diet-fed female mice

Consumption of diets high in fat, sugar and salt (Western diet, WD) is associated with accelerated arterial stiffening, a major independent risk factor for cardiovascular disease (CVD). Obese women are more prone to develop arterial stiffening leading to more frequent and severe CVD compared to men. As tissue transglutaminase (TG2) has been implicated in vascular stiffening, our goal herein was to determine the efficacy of cystamine, a non-specific TG2 inhibitor, at reducing vascular stiffness in female mice chronically fed a WD. Three experimental groups of female mice were created. One was fed regular chow diet (CD) for 43 weeks starting at four weeks of age. The second was fed a WD for the same 43 weeks, whereas a third cohort was fed WD, but also received cystamine (216 mg/kg/d) in the drinking water during the last eight weeks on the diet (WD+C). All vascular stiffness parameters assessed, including aortic pulse wave velocity and the incremental modulus of elasticity of isolated femoral and mesenteric arteries, were significantly increased in WD- vs. CD-fed mice, and reduced in WD+C vs. WD-fed mice. These changes coincided with respectively augmented and diminished vascular wall collagen and F-actin content, with no associated effect in blood pressure. In cultured human vascular smooth muscle cells, cystamine reduced TG2 activity, F-actin/G-actin ratio, collagen compaction capacity and cellular stiffness. We conclude that cystamine treatment represents an effective approach to reduce vascular stiffness in female mice in the setting of WD consumption, likely due to its TG2 inhibitory capacity.

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.

192 Study of endothelial function and vascular stiffness in patients affected by dilated cardiomyopathy on treatment with sacubitril/valsartan

Aims It has already been demonstrated the efficacy of sacubitril/valsartan in the treatment of heart failure with reduced ejection fraction, but many of its properties are still unknown especially regarding its effects on endothelial dysfunction and arterial stiffness. Methods and results To this purpose, a longitudinal study involving 15 patients with dilated cardiomyopathy with reduced left ventricular ejection fraction (LVEF) was started; the purpose was collecting at the beginning and at the end of the study blood pressure measurements, transthoracic echocardiography images, parameters of endothelial function with peripheral arterial tonometry (EndoPAT®), and non-invasive evaluation of the aortic stiffness parameters by using applanation tonometry (SphygmoCor® Px system). Aortic stiffness parameters weren’t different at 6 months, compared to baseline. There was a slight, not significant increase in augmentation pressure (P = 0.889), augmentation index (P = 0.906), and sphygmic wave velocity (P = 0.263). Systolic, diastolic, and differential central arterial pressure didn’t change. RHI (reactive hyperaemia index) increased significantly after 6 months (P = 0.001) as well as augmentation index corrected for 75 b.p.m. Ejection fraction (32.21% ± 5.7 to 38.43% ± 8.4; P = 0.010) and diastolic dysfunction degree (P = 0.021) improved significantly. Mitral regurgitation improvement wasn’t statistically significant (P = 0.116). Tricuspid annular plane systolic excursion didn’t change while pulmonary systolic arterial pressure increased, although not significantly (22.83 mmHg ± 4 to 27.33 mmHg ± 6; P = 0.068) and within the normal range values. Conclusions Sacubitril/valsartan can improve endothelial function significantly in patients with dilated cardiomyopathy and reduced LVEF. It can also improve left ventricular function, mitral regurgitation, and diastolic function. Conversely, this drug seems to have no effects on vascular stiffness.

Effect of empagliflozin on ketone bodies in patients with stable chronic heart failure

Background Recent studies indicated that sodium glucose cotransporter (SGLT)2 inhibition increases levels of ketone bodies in the blood in patients with type 1 and 2 diabetes. Other studies suggested that in patients with chronic heart failure (CHF), increased myocardial oxygen demand can be provided by ketone bodies as a fuel substrate. Experimental studies reported that ketone bodies, specifically beta-hydroxybutyrate (β-OHB) may increase blood pressure (BP) by impairing endothelium-dependant relaxation, thereby leading to increased vascular stiffness. In our study we assessed whether the SGLT 2 inhibition with empagliflozin increases ketone bodies in patients with stable CHF and whether such an increase impairs BP and vascular function. Methods In a prospective, double blind, placebo controlled, parallel-group single centre study 75 patients with CHF (left ventricular ejection fraction 39.0 ± 8.2%) were randomised (2:1) to the SGLT-2 inhibitor empagliflozin 10 mg orally once daily or to placebo, 72 patients completed the study. After a run-in phase we evaluated at baseline BP by 24 h ambulatory blood pressure (ABP) monitoring, vascular stiffness parameters by the SphygmoCor system (AtCor Medical, Sydney, NSW, Australia) and fasting metabolic parameters, including β-OHB by an enzymatic assay (Beckman Coulter DxC 700 AU). The same measurements were repeated 12 weeks after treatment. In 19 of the 72 patients serum levels of β-OHB were beneath the lower border of our assay (< 0.05 mmol/l) therefore being excluded from the subsequent analysis. Results In patients with stable CHF, treatment with empagliflozin (n = 36) was followed by an increase of β-OHB by 33.39% (p = 0.017), reduction in 24 h systolic (p = 0.038) and diastolic (p = 0.085) ABP, weight loss (p = 0.003) and decrease of central systolic BP (p = 0.008) and central pulse pressure (p = 0.008). The increase in β-OHB was related to an attenuated decrease of empagliflozin-induced 24 h systolic (r = 0.321, p = 0.069) and diastolic (r = 0.516, p = 0.002) ABP and less reduction of central systolic BP (r = 0.470, p = 0.009) and central pulse pressure (r = 0.391, p = 0.033). No significant changes were seen in any of these parameters after 12 weeks of treatment in the placebo group (n = 17). Conclusion In patients with stable CHF ketone bodies as assessed by β-OHB increased after treatment with empagliflozin. This increase led to an attenuation of the beneficial effects of empagliflozin on BP and vascular parameters. Trial registration The study was registered at http://www.clinicaltrials.gov (NCT03128528).

RAGE antagonist peptide mitigates AGE-mediated endothelial hyperpermeability and accumulation of glycoxidation products in human ascending aortas and in a murine model of aortic aneurysm

Background: Aortic dissection and aneurysm are the result of altered biomechanical forces associated with structural weakening of the aortic wall caused by genetic or acquired factors. Current guidelines recommend replacement of the ascending aorta when the diameter is >5.5 cm in tricuspid aortic valve patients. Aortopathies are associated with altered wall stress and stiffness as well as endothelial cell dysfunction and synthetic vascular smooth muscle cell (VSMC) phenotype. We reported that these mechanisms are mediated by glycoxidation products [Reactive oxygen species (ROS) and Advance Glycation End products (AGE)]. This study addresses the role of glycoxidation on endothelial function and AGE-mediated aortic stiffness. Hypothesis and aims: Here we investigate how circulating glycation products infiltrate the aortic wall via AGE-mediated endothelial hyperpermeability and contribute to both VSMC synthetic phenotype and extracellular matrix (ECM) remodeling in vivo and ex vivo. We also study how RAGE antagonist peptide (RAP) can rescue the effect of AGEs in vitro and in vivo in eNOS-/- vs WT mice. Methods and results: Human ascending aortas (n=30) were analyzed for AGE, ROS, and ECM markers. In vitro glycation was obtained by treating VSMC or human and murine aortas with glyoxal. Endothelial permeability was measured under glycation treatment. Vascular stiffness was measured by a pressure myograph comparing wild-type mice in the absence of presence of glyoxal. eNOS-/- mice, a model of increased endothelial permeability, were treated for 28 days with hyperlipidemic diet and Angiotensin II (1000ng/kg/min) with or without anti-glycation treatment (RAP 20mg/kg). Echo data of aortic diameter were collected. Murine vascular stiffness was measured by a pressure myograph (n=5/group). Glycoxidation products were detected in all human aortas independently of aortic diameter, with stronger accumulation on the lumen and the adventitia layer. AGEs increased endothelial permeability, induce synthetic phenotypic switch in human VSMCs, and inhibit cell migration. RAP pre-treatment rescue the effect of glyoxal on endothelial cells. Ex vivo glycation treatment of murine arteries impacted on ECM and increased stiffness. Aortic stiffness was higher in eNOS-/- vs WT mice. Ang II-mediated aortopathies results in aortic dilation, and AGE/ROS accumulation, which is rescued by RAGE antagonist peptide treatment of eNOS-/- mice. Conclusions: Glycoxidation reaction mediates EC permeability, VSMCs phenotype, and ECM remodeling leading to dysfunctional microstructure of the ascending aorta, altered vascular stiffness and increasing aortic susceptibility to dilation and rupture. Moreover, we show that RAP can mitigate AGE-mediated endothelial hyper-permeability in vitro and impact on ascending aneurysm in vivo

Assessment of Magnesium level Among Hemodialysis Patients and Its Relation to Vascular Stiffness

Background The pathogenesis of vascular calcification in Chronic kidney disease (CKD) patients is multifactorial and complicated. It has been proposed that Magnesium (Mg) may be implicated in the process of vascular calcification on various levels. Aim This study aims to assess the level of magnesium in hemodialysis patients and its relation to the vascular stiffness. Patients and methods 100 prevalent hemodialysis patients were included in the study and they were clinically stable with absence of cardiovascular complications, all patients underwent the following laboratory investigation including complete blood picture, median of magnesium level over 3 months, electrolytes, ipth, lipid profile and radiological investigations including transthoracic echocardiography and carotid duplex. Results The studied population was divided into two groups, group I included 68 patients with normal mg level and group II included 32 patients with low mg level. There was statistically significant difference between the two groups as regard hemoglobin level (pvalue=0.033), otherwise there was no statistically significant difference as regard other laboratory and radiological investigations. Then they were divided into another two groups according to the presence of mitral valve calcification (MVC), group III involved 85 patients without MVC and group IV involved 15 patients with MVC. There was statistically significant difference between 2 groups as regard aortic wave pulse velocity (aPWV) with (pvalue=0.002), presence of plaques with (pvalue &lt;0.001) and intimal media thickness with (pvalue&lt;0.001). Another group was divided according to presence of aortic valve calcification (AVC) into two groups, first group V included 39 patients without AVC and second group VI included 61 patients with AVC. There was statistically significant difference between two groups as regard age with (pvalue&lt;0.001), ipth with (pvalue=0.033), presence of plaques with (pvalue=0.048) and intimal media thickness with (pvalue&lt;0.001). Conclusion There was high prevalence of vascular calcification among hemodialysis patients which may be related to age and hyperparathyroidism but without statistically significant correlation to Mg level.

Vascular stiffness in children born after frozen or fresh embryo transfer. A cardiac magnetic resonance imaging study of 8 to 9 year old children

Background Vascular stiffness increases during childhood, and increased vascular stiffness is associated with symptomatic cardiovascular disease in adults with metabolic syndrome. In comparison with naturally conceived children (NC), children conceived after in-vitro fertilization by frozen (FET) or fresh embryo transfer (Fresh ET) are at risk of being large- and small-for-gestational-age, respectively. Epigenetic modulation during assisted reproductive technologies (ART) is suggested to influence cardiovascular risk factors, and recent literature suggests that children conceived after ART are at increased risk of insulin resistance, endothelial dysfunction and arterial hypertension. Such changes may be associated with increased vascular stiffness, but it is not yet been examined directly. Purpose We investigated if ART children are at increased risk of aortic distensibility and pulse-wave velocity. Methods 150 children aged 8–9 years conceived after FET (n=50), Fresh ET (n=50) or by natural conception (NC, n=50) were studied with magnetic resonance imaging. Conductance artery stiffness was determined from aortic distensibility and aortic pulse-wave velocity (PWV). Data were analyzed with blinding according to treatment group. Based on a conservative estimate for the common SD for the difference between groups of 1.5 mm2/mmHg, 36 children were required in each group to detect a difference in aortic distensibility of 10%, which corresponds to a 5 year age difference, with an alpha of 0.05 (double-sided) and a beta of 0.80. We aimed for 50 children in each group to allow for dropouts and non-analyzable scans, and to allow for further determinations. The effects of potential confounders on the effect of conception method on ascending aorta distensibility and total aortic PWV were tested stepwise in four linear regression models (Figure 1). Results Child groups were comparable with respect to anthropometric measures (Table 1). No differences were observed in systolic or diastolic blood pressure, cardiac output, total peripheral resistance, or in aortic distensibility (Ascending aorta distensibility: FET, ascending aorta 11.12±3.55 10–3 mm2/mmHg; Fresh ET 11.77±2.97 10–3 mm2/mmHg; NC 11.43±2.82 10–3 mm2/mmHg) (ANOVA-p=0.58) or aortic PWV (PWV of total aorta: FET, 3.69±0.75 m/s; Fresh ET, 3.49±0.31 m/s; NC, 3.59±0.61 m/s) (ANOVA-p=0.26). The effect of ART remained non-significant after adjustment for child sex, maternal BMI at early pregnancy, and maternal educational level (Figure 1). Conclusion The effects of ART on aortic distensibility were not statistically significant, but in the direction of the hypothesis of stiffer conductance arteries from frozen embryo transfer. The confidence interval was relatively wide, and the results suggest that the difference between frozen and fresh embryo transfer may in fact correspond to an age difference of more than 5 years. FUNDunding Acknowledgement Type of funding sources: Foundation. Main funding source(s): The Novo Nordisk Foundation Table 1 Figure 1

Evaluation of the effectiveness of statin and spironolactone by the influence on indicators of vascular stiffness in patients with arterial hypertension

Introduction The possibility of slowing down vascular remodeling in hypertensive patients with the combined effect of antihypertensive drugs and statins has been studied in unitary studies. The effect of spironolactone on vascular stiffness in relation to the severity of the hypotensive effect in combination therapy has also been insufficiently studied. The aim of the research was to study the dynamics vascular stiffness parameters in hypertension patients of high/very high cardiovascular risk in addition rosuvastatin or spironolactone to combined two-component amlodipine and lisinopril therapy. Methods 90 patients (46 men and 44 women aged 51.6±8.5) with hypertension were randomized into groups: the first group received a fixed combination of amlodipine/lisinopril, the 2nd one followed the same regimen of therapy with addition of 20 mg rosuvastatin, the third - in addition to the combination of amlodipine / lisinopril received 25 mg of spironolactone. The office and ambulatory blood pressure (BP), central (aortic) BP, augmentation index (AIx), carotid-femoral and carotid-radial pulse wave velocity (PWV) were evaluated before and after a 24-week follow-up period. Results The office and average daily blood pressure decreased against the background of all therapy regimens (all p&lt;0.0001). The degree of decrease in the above parameters was more pronounced under the influence of spironolactone, compared with taking a combination of amlodipine / lisinopril (office systolic BP (SBP) p=0.04 and diastolic BP (DBP) p=0.002, average daily SBP p=0.02 and DBP p=0.014) and office DBP in comparison with the group of additional administration of rosuvastatin (p=0.02). A decrease in central BP and AIx was noted in all groups. A more pronounced decrease in AIx occurred in the statin supplementation group relative to the standard treatment group (−5.8% and −9.0%, respectively, p=0.036). Carotid-femoral PWV significantly decreased in all groups (−0.9±1.5 m/s, −0.7±1.4 m/s, −2.2±2.6 m/s, respectively), in greater degree in the spironolactone addition group compared with the statin supplementation group (p=0.036). Carotid-radial PWV to the same extent significantly decreased only in the second (from 9.5±1.8 to 8.8±1.1 m/s (p=0.034)) and the third (from 9.8±1.3 to 8.4±1.3 m/s (p=0.0002)) groups. Conclusions The addition of a statin to a two-component combination of amlodipine / lisinopril in the treatment of hypertensive patients had an additional effect on the elastic properties of the aorta, in the form of a decrease in the augmentation index, and peripheral arteries, in the form of a decrease in PWV. The addition of spironolactone to standard therapy was accompanied by a significant increase in the antihypertensive effect and a decrease in aortic stiffness in the form of a more pronounced decrease in PWV in the carotid-femoral and carotid-radial areas. FUNDunding Acknowledgement Type of funding sources: None.