Association between arterial stiffness and platelet activation

Role of the NO-GC/cGMP signaling pathway in platelet biomechanics

Cyclic guanosine monophosphate (cGMP) is a second messenger produced by the NO-sensitive guanylyl cyclase (NO-GC). The NO-GC/cGMP pathway in platelets has been extensively studied. However, its role in regulating the biomechanical properties of platelets has not yet been addressed and remains unknown. We therefore investigated the stiffness of living platelets after treatment with the NO-GC stimulator riociguat or the NO-GC activator cinaciguat using scanning ion conductance microscopy (SICM). Stimulation of human and murine platelets with cGMP-modulating drugs decreased cellular stiffness and downregulated P-selectin, a marker for platelet activation. We also quantified changes in platelet shape using deep learning-based platelet morphometry, finding that platelets become more circular upon treatment with cGMP-modulating drugs. To test for clinical applicability of NO-GC stimulators in the context of increased thrombogenicity risk, we investigated the effect of riociguat on platelets from human immunodeficiency virus (HIV)-positive patients taking abacavir sulfate (ABC)-containing regimens. Our results corroborate a functional role of the NO-GC/cGMP pathway in platelet biomechanics, indicating that biomechanical properties such as stiffness or shape could be used as novel biomarkers in clinical research.

Trends among platelet function, arterial calcium, and vascular function measures

Arterial tonometry and vascular calcification measures are useful in cardiovascular disease (CVD) risk assessment. Prior studies found associations between tonometry measures, arterial calcium, and CVD risk. Activated platelets release angiopoietin-1 and other factors, which may connect vascular structure and platelet function. We analyzed arterial tonometry, platelet function, aortic, thoracic and coronary calcium, and thoracic and abdominal aorta diameters measured in the Framingham Heart Study Gen3/NOS/OMNI-2 cohorts (n = 3,429, 53.7% women, mean age 54.4 years ±9.3). Platelet reactivity in whole blood or platelet-rich plasma was assessed using 5 assays and 7 agonists. We analyzed linear mixed effects models with platelet reactivity phenotypes as outcomes, adjusting for CVD risk factors and family structure. Higher arterial calcium trended with higher platelet reactivity, whereas larger aortic diameters trended with lower platelet reactivity. Characteristic impedance (Zc) and central pulse pressure positively trended with various platelet traits, while pulse wave velocity and Zc negatively trended with collagen, ADP, and epinephrine traits. All results did not pass a stringent multiple test correction threshold (p < 2.22e-04). The diameter trends were consistent with lower shear environments invoking less platelet reactivity. The vessel calcium trends were consistent with subclinical atherosclerosis and platelet activation being inter-related.

Severe COVID-19-A Review of Suggested Mechanisms Based on the Role of Extracellular Matrix Stiffness

The severity of COVID-19 commonly depends on age-related tissue stiffness. The aim was to review publications that explain the effect of microenvironmental extracellular matrix stiffness on cellular processes. Platelets and endothelial cells are mechanosensitive. Increased tissue stiffness can trigger cytokine storm with the upregulated expression of pro-inflammatory cytokines, such as tumor necrosis factor alpha and interleukin IL-6, and tissue integrity disruption, leading to enhanced virus entry and disease severity. Increased tissue stiffness in critically ill COVID-19 patients triggers platelet activation and initiates plague formation and thrombosis development. Cholesterol content in cell membrane increases with aging and further enhances tissue stiffness. Membrane cholesterol depletion decreases virus entry to host cells. Membrane cholesterol lowering drugs, such as statins or novel chitosan derivatives, have to be further developed for application in COVID-19 treatment. Statins are also known to decrease arterial stiffness mitigating cardiovascular diseases. Sulfated chitosan derivatives can be further developed for potential use in future as anticoagulants in prevention of severe COVID-19. Anti-TNF-α therapies as well as destiffening therapies have been suggested to combat severe COVID-19. The inhibition of the nuclear factor kappa-light-chain-enhancer of activated B cells pathway must be considered as a therapeutic target in the treatment of severe COVID-19 patients. The activation of mechanosensitive platelets by higher matrix stiffness increases their adhesion and the risk of thrombus formation, thus enhancing the severity of COVID-19.

Arterial stiffness and atherosclerosis in systemic lupus erythematosus patients

Introduction

Systemic lupus erythematosus (SLE) is characterized by early atherothrombosis. Pulse wave velocity (PWV) is a promising tool for the diagnosis of early vascular remodelling and initial atherosclerotic plaque formation. Our objective was to evaluate PWV and its relationship with coronary atherosclerosis and thrombotic biomarkers in patients with SLE.

Material and methods

In 26 patients with SLE with stable clinical conditions, mean age of 39.1 ±11.7 years and without a history of coronary artery disease, multidetector computed tomography (MDCT)-based coronary calcium scoring (CACS) was performed and PWV measured.

Laboratory evaluation included serum levels of anticardiolipin and anti-β2-glycoprotein antibodies (anti-β2-GPI), lupus anticoagulant (LA), D-dimers, thrombin–antithrombin complexes (TAT), and von Willebrand factor (vWF).

Results

Multidetector computed tomography revealed coronary calcifications in 8 (30.8%) patients and the median CACS was 52.4 HU (range 2–843.2). The mean PWV was 9.0 ±3.2 m/s and was higher in patients aged > 50 years (+33.7% vs. < 50 years), those with positive LA (+28.2% vs. LA negative), TAT ≥ 10 μg/l (+18.1% vs. < 10 μg/l), vWF ≥ 200 IU/dl (+51.8% vs. < 200 IU/dl) and with coronary atherosclerosis (CACS > 0; +21.4% vs. CACS = 0).

In contrast, the duration of the disease, D-dimers, anticardiolipin, and anti-β2-GPI antibodies did not influence PWV. In the group without atherosclerosis (CACS = 0, n =18), patients with vWF ≥ 200 IU/dl had a 19.3% higher PWV compared to the rest.

Conclusions

In patients with SLE, PWV was associated with the presence of coronary atherosclerotic lesions in MDCT. Furthermore, arterial stiffness was higher in patients with markers of endothelial dysfunction and a prothrombotic state, suggesting their contribution to the early stages of arterial remodelling in SLE.

Urinary Proteomic Profile of Arterial Stiffness Is Associated With Mortality and Cardiovascular Outcomes

Background

The underlying mechanisms of arterial stiffness remain not fully understood. This study aimed to identify a urinary proteomic profile to illuminate its pathogenesis and to determine the prognostic value of the profile for adverse outcomes.

Methods and Results

We measured aortic stiffness using pulse wave velocity (PWV) and analyzed urinary proteome using capillary electrophoresis coupled with mass spectrometry in 669 randomly recruited Flemish patients (mean age, 50.2 years; 51.1% women). We developed a PWV‐derived urinary proteomic score (PWV‐UP) by modeling PWV with proteomics data at baseline through orthogonal projections to latent structures. PWV‐UP that consisted of 2336 peptides explained the 65% variance of PWV, higher than 36% explained by clinical risk factors. PWV‐UP was significantly associated with PWV (adjusted β=0.73 [95% CI, 0.67–0.79]; P<0.0001). Over 9.2 years (median), 36 participants died, and 75 experienced cardiovascular events. The adjusted hazard ratios (+1 SD) were 1.46 (95% CI, 1.08–1.97) for all‐cause mortality, 2.04 (95% CI, 1.07–3.87) for cardiovascular mortality, and 1.39 (95% CI, 1.11–1.74) for cardiovascular events (P≤0.031). For PWV, the corresponding estimates were 1.25 (95% CI, 0.97–1.60), 1.35 (95% CI, 0.85–2.15), and 1.22 (95% CI, 1.02–1.47), respectively (P≥0.033). Pathway analysis revealed that the peptides in PWV‐UP mostly involved multiple pathways, including collagen turnover, cell adhesion, inflammation, and lipid metabolism.

Conclusions

PWV‐UP was highly associated with PWV and could be used as a biomarker of arterial stiffness. PWV‐UP, but not PWV, was associated with all‐cause mortality and cardiovascular mortality, implying that PWV‐UP–associated peptides may be multifaceted and involved in diverse pathological processes beyond arterial stiffness.

Vascular protective effect of aspirin and rivaroxaban upon endothelial denudation of the mouse carotid artery

While in recent trials the dual pathway inhibition with aspirin plus rivaroxaban has shown to be efficacious in patients with atherosclerotic cardiovascular disease, little is known about the effects of this combination treatment on thrombus formation and vascular remodelling upon vascular damage. The aim of this study was to examine the effects of aspirin and/or rivaroxaban on injury-induced murine arterial thrombus formation in vivo and in vitro, vessel-wall remodelling, and platelet-leukocyte aggregates. Temporary ligation of the carotid artery of C57BL/6 mice, fed a western type diet, led to endothelial denudation and sub-occlusive thrombus formation. At the site of ligation, the vessel wall stiffened and the intima-media thickened. Aspirin treatment antagonized vascular stiffening and rivaroxaban treatment led to a positive trend towards reduced stiffening. Local intima-media thickening was antagonized by both aspirin or rivaroxaban treatment. Platelet-leukocyte aggregates and the number of platelets per leukocyte were reduced in aspirin and/or rivaroxaban treatment groups. Furthermore, rivaroxaban restricted thrombus growth and height in vitro. In sum, this study shows vascular protective effects of aspirin and rivaroxaban, upon vascular injury of the mouse artery.

Caffeine Augments the Prothrombotic but Not the Fibrinolytic Response to Exercise

Caffeine, a popular ergogenic supplement, induces neural and vascular changes that may influence coagulation and/or fibrinolysis at rest and during exercise.

PURPOSE

The purpose of this study was to assess the effect of a single dose of caffeine on measures of coagulation and fibrinolysis before and after a single bout of high-intensity exercise.

METHODS

Forty-eight men (age, 23 ± 3 yr; body mass index, 24 ± 3 kg·m) completed two trials, with 6 mg·kg of caffeine (CAFF) or placebo (PLAC), in random order, followed by a maximal cycle ergometer test. Plasma concentrations of fibrinogen, factor VIII antigen, active tissue plasminogen activator (tPA:c), tissue plasminogen activator antigen (tPA:g), and active plasminogen activator inhibitor-1 (PAI-1:c) were assessed at baseline and immediately after exercise.

RESULTS

Exercise led to significant changes in tPA:c (Δ 8.5 ± 4.36 IU·mL for CAFF, 6.6 ± 3.7 for PLAC), tPA:g (Δ 2.4 ± 3.2 ng·mL for CAFF, 1.9 ± 3.1 for PLAC), fibrinogen (Δ 30.6 ± 61.4 mg·dL for CAFF, 28.1 ± 66.4 for PLAC), and PAI-1:c (Δ -3.4 ± 7.9 IU·mL for CAFF, -4.0 ± 12.0 for PLAC) (all P < 0.05), but no effect of condition or time-condition interactions were observed. Main effects of time, condition, and a significant time-condition interaction were observed for factor VIII, which increased from 1.0 ± 0.4 IU·mL to 3.3 ± 1.3 IU·mL with CAFF and 1.0 ± 0.4 IU·mL to 2.4 ± 0.9 IU·mL with PLAC.

CONCLUSIONS

Coagulation potential during exercise is augmented after caffeine intake, without a similar increase in fibrinolysis. These results suggest caffeine intake may increase risk of a thrombotic event during exercise.

Effects of interval walking training compared to normal walking training on cognitive function and arterial function in older adults: a randomized controlled trial

PURPOSE

This study investigated whether interval walking training (IWT) improves cognitive function and arterial function in older adults.

METHODS

A total of 68 older adults registered in clinical trials (mean age ± standard deviation, 70 ± 4 years) were randomly assigned to two groups: one group performed IWT (n = 34), and the other performed normal walking training (NWT, n = 34). Participants in the IWT group performed five or more sets of low-intensity walking (duration: 3 min per set; peak aerobic capacity for walking: 40%) followed by high-intensity walking (duration: 3 min per set; peak aerobic capacity for walking: > 70%). The NWT group walked at approximately 50% of the peak aerobic capacity for walking. The IWT and NWT were performed for 20 weeks. Trail making test-A and B and carotid-femoral pulse wave velocity (cfPWV) were measured in both groups at baseline and again at the end of the 20-week study period.

RESULTS

Compared to baseline, time for trail making test-A (IWT group: P = 0.00004, NWT group: P = 0.000006) and B (IWT group: P = 0.03, NWT group: P = 0.003) as well as cfPWV (IWT group: P = 0.000002, NWT group: P = 0.03) decreased significantly after the 20-week study period in both groups. However, cfPWV in the IWT group decreased significantly more than that in the NWT group (P = 0.03).

CONCLUSION

These results suggested that although both IWT and NWT were similarly effective at improving cognitive function, IWT reduced central arterial stiffness more than NWT.

In healthy normotensive subjects age and blood pressure better predict subclinical vascular and cardiac organ damage than atherosclerosis biomarkers

PURPOSE

Only few studies evaluated biomarkers useful for defining the cardiovascular risk of a subject in a pre-clinical condition (i.e. healthy subjects). In this context we sought to determine the relationships of Plasminogen activator inhibitor type 1 (PAI-1), P-Selectin, Tissue Inhibitors Metalloproteinases type 1 (TIMP-1) and Cystatin-C with subclinical Target Organ Damage (TOD) in normotensive and normoglycemic subjects without known cardiovascular and kidney diseases.

MATERIALS AND METHODS

480 blood donors participated at the present analysis. TOD was evaluated as Pulse Wave Velocity (PWV), Left Ventricular Hypertrophy (LVH) and Intima Media Thickness (IMT) and carotid plaque presence) grouped together under carotid TOD.

RESULTS

3.1% of the subjects showed a PWV higher than 10 m/sec with those subjects exerting significantly lower values of P-Selectine (0.068 ± 0.015 vs 0.08 ± 0.036 mg/L, p = .014). 8.8% of the subjects showed carotid TOD that was associated with higher Cystatin-C values (0.67 ± 0.17 vs 0.63 ± 0.14 mg/L, p = .045). Finally 23.8% of the subjects showed LVH with no significant differences regarding biomarkers. Despite some significant correlations between biomarkers and TOD, at the multivariate analysis none came out to be as significant predictor of the assessed TOD.

CONCLUSIONS

in normotensive and normoglycemic healthy subjects, the evaluated biomarkers of atherosclerotic process didn't show any significant association with cardiac, carotid and vascular TOD while age and BP are its principal predictors.

The role of extracellular matrix stiffness in megakaryocyte and platelet development and function

The extracellular matrix (ECM) is a key acellular structure in constant remodeling to provide tissue cohesion and rigidity. Deregulation of the balance between matrix deposition, degradation, and crosslinking results in fibrosis. Bone marrow fibrosis (BMF) is associated with several malignant and nonmalignant pathologies severely affecting blood cell production. BMF results from abnormal deposition of collagen fibers and enhanced lysyl oxidase-mediated ECM crosslinking within the marrow, thereby increasing marrow stiffness. Bone marrow stiffness has been recently recognized as an important regulator of blood cell development, notably by modifying the fate and differentiation process of hematopoietic or mesenchymal stem cells. This review surveys the different components of the ECM and their influence on stem cell development, with a focus on the impact of the ECM composition and stiffness on the megakaryocytic lineage in health and disease. Megakaryocyte maturation and the biogenesis of their progeny, the platelets, are thought to respond to environmental mechanical forces through a number of mechanosensors, including integrins and mechanosensitive ion channels, reviewed here.

Impact of increased visceral adiposity with normal weight on the progression of arterial stiffness in Japanese patients with type 2 diabetes

OBJECTIVE

Normal-weight abdominal obesity has been reported to be associated with poor mortality. We aimed to investigate the impact of increased visceral adiposity with normal weight (OB(-)VA(+)) on the progression of arterial stiffness in patients with type 2 diabetes.

METHODS

This was a cross-sectional study of 414 patients with type 2 diabetes (mean age 64±12 years; 40.3% female). Visceral fat area (VFA, cm(2)) was measured by a dual bioelectrical impedance analyzer. Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV, cm/s). Patients were divided into four groups by VFA and body mass index (BMI, kg/m(2)) as the following: BMI<25 kg/m(2) and VFA<100 cm(2) (obesity (OB)(-)visceral adiposity (VA)(-)), BMI≥25 kg/m(2) and VFA<100 cm(2) (OB(+)VA(-)), BMI<25 kg/m(2) and VFA≥100 cm(2) (OB(-)VA(+)), and BMI≥25 kg/m(2) and VFA≥100 cm(2) (OB(+)VA(+)). Multivariate linear regression analysis was done to determine the impact of OB(-)VA(+) on arterial stiffness.

RESULTS

Among the patients, 7.2% were OB(-)VA(+) with higher baPWV levels (1956±444 cm/s) than those with OB(+)VA(-) (1671±416 cm/s, p=0.014), those with OB(+)VA(+) (1744±317 cm/s, p=0.048), and those with OB(-)VA(-) (1620±397 cm/s, p=0.024). In multivariate linear regression analysis, OB(-)VA(+) remained independently associated with baPWV (standardized β 0.184, p=0.001).

CONCLUSIONS

This study provides evidence for the burden of arterial stiffness in OB(-)VA(+) patients with type 2 diabetes; therefore, evaluation of visceral adiposity is of clinical relevance for the better management of non-obese individuals as well as obese populations.

Brachial-ankle pulse wave velocity and mean platelet volume as predictive values after percutaneous coronary intervention for long-term clinical outcomes in Korea: A comparable and additive study

This study aimed to determine the association of the brachial-ankle pulse wave velocity (baPWV) and mean platelet volume (MPV) with the development of adverse outcomes after percutaneous coronary intervention (PCI). The baPWV and MPV were analyzed in 372 patients who underwent PCI, with the primary endpoint as cardiac death. The secondary endpoint was cardiovascular events (CVE): a composite of cardiac death, myocardial infarction (MI), target vessel revascularization (TVR), ischemic stroke, and stent thrombosis (ST). During the follow-up period (mean, 25.8 months), there were 21 cardiac deaths, 10 MIs including four events of ST, seven ischemic strokes, and 29 TVRs. The baPWV cut-off level was set at 1672 cm/s using the receiver operating characteristic curve; the sensitivity and specificity was 85.7 and 60.1%, respectively, to differentiate between the groups with and without cardiac death. The MPV cut-off level was set at 8.20 fL using the receiver operating characteristic curve; the sensitivity and specificity were 81 and 53.3%, respectively, to differentiate between the groups with and without cardiac death. Kaplan-Meier analysis revealed that the higher baPWV group (≥ 1672 cm/s) had a significantly higher cardiac death and CVE rate than the lower baPWV group (<1672 cm/s) (11.4 vs. 1.4%, log-rank: p < 0.0001; 25.3 vs. 7.5%, log-rank: p < 0.0001; respectively), and the higher MPV group (median, >8.20 fL,) had a significantly higher cardiac death and CVE rate than the lower MPV group (≤ 8.20 fL) (9.4 vs. 2.1%, log-rank: p = 0.0026; 23.8 vs. 6.8%, log-rank: p < 0.0001; respectively). Furthermore, the high baPWV and MPV groups were significantly associated with an increased risk of cardiac death. These results show that baPWV and MPV are predictive markers after PCI for cardiac death; they are also additively associated with a higher risk of cardiac death.

High platelet reactivity is associated with vascular function in patients after percutaneous coronary intervention receiving clopidogrel

BACKGROUND

In the present study, we evaluated the association of platelet reactivity with vascular function in patients after percutaneous coronary intervention receiving clopidogrel treatment.

METHODS

We enrolled 150 patients with stable CAD receiving clopidogrel regimen (75 mg/d), 1 month after percutaneous coronary intervention. Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic stiffness and augmentation index (AIx) as an index of arterial wave reflections. High on treatment platelet reactivity (HPR) was evaluated using VerifyNow Assay. VerifyNow reports its results in P2Y12 reaction units (PRU), and the diagnostic cutoff value is 230 PRU. Patients were evaluated prospectively up to 24 months. The primary end point was a composite of death from cardiovascular causes, nonfatal major cardiovascular events and hospitalization for cardiovascular causes.

RESULTS

There was no difference in the basic clinical and demographic characteristics between subjects with HPR and non-HPR. Subjects with high on treatment platelet reactivity and PRU>230 had significantly increased PWV (8.81 ± 2.25 m/s vs. 7.69 ± 1.95 m/s, p = 0.001) and AIx (25.27 ± 8.67% vs. 20.87 ± 10.57%, p = 0.04) compared to subjects with PRU≤230. PWV was also associated with PRU (r = 0.23, p = 0.02). HPR was associated with significantly increased risk of primary end point [HR = 5.38, 95%CI:(1.15, 26.04), p = 0.03].

CONCLUSIONS

Increased platelet reactivity is associated with impaired arterial stiffness in patients after percutaneous coronary intervention receiving clopidogrel treatment, highlighting another clinical factor implicated in individual platelet response to antiplatelet therapy. Moreover, increased platelet reactivity is associated with adverse outcome in these patients.

Predictive value of brachial-ankle pulse wave velocity for long-term clinical outcomes after percutaneous coronary intervention in a Korean cohort

OBJECTIVE

The aim of this study was to determine the associations of brachial-ankle pulse wave velocity (baPWV), high-sensitivity cardiac troponin T (hs-cTnT) and N-terminal pro-B type natriuretic peptide (NT-proBNP) with the development of adverse outcomes after percutaneous coronary intervention (PCI).

METHODS

The baPWV, hs-cTnT and NT-proBNP were analyzed in 372 patients who underwent PCI. The primary endpoint was cardiac death.

RESULTS

There were 21 events of cardiac death during a mean of 25.8 months of follow-up. When the baPWV cut-off level was set to 1672 cm/s using the receiver operating characteristic curve, the sensitivity was 85.7% and the specificity was 60.1% for differentiating between the group with cardiac death and the group without cardiac death. Kaplan-Meier analysis revealed that the higher baPWV group (≥1672 cm/s) had a significantly higher cardiac death rate than the lower baPWV group (<1672 cm/s) (11.4% vs. 1.4%, log-rank: P<0.0001). This value was more useful in patients with myocardial injury (hs-cTnT≥0.1 ng/mL) or heart failure (NT-proBNP≥450 pg/mL).

CONCLUSIONS

The results of this study show that high baPWV is a predictive marker for cardiac death after PCI.

Associations between arterial stiffness and platelet activation in normotensive overweight and obese young adults

Obese individuals have elevated platelet activation and arterial stiffness, but the strength and temporality of the relationship between these factors remain unclear. We aimed to determine the effect of increased arterial stiffness on circulating platelet activity in overweight/obese young adults. This analysis included 92 participants (mean age 40 years, 60 women) in the Slow Adverse Vascular Effects of excess weight (SAVE) trial, a clinical trial examining the effects of a lifestyle intervention with or without sodium restriction on vascular health in normotensive overweight/obese young adults. Carotid-femoral (cf), brachial-ankle (ba) and femoral-ankle (fa) pulse wave velocity (PWV) served as measures of arterial stiffness and were measured at baseline and 6, 12 and 24 months follow-up. Platelet activity was measured as plasma β-thromboglobulin (β-TG) at 24 months. Higher plasma β-TG was correlated with greater exposure to elevated cfPWV (p = 0.02) and baPWV (p = 0.04) during the preceding two years. After adjustment for serum leptin, greater exposure to elevated baPWV remained significant (p = 0.03) and exposure to elevated cfPWV marginally significant (p = 0.054) in predicting greater plasma β-TG. Greater arterial stiffness, particularly central arterial stiffness, predicts greater platelet activation in overweight/obese individuals. This relationship might partly explain the association between increased arterial stiffness and incident atherothrombotic events.

Mean Platelet Volume Associated With Aortic Distensibility, Chronic Inflammation, and Diabetes in Patients With Stable Coronary Artery Disease

We aimed to assess the effective factors on high mean platelet volume (MPV) in patients with stable coronary artery disease (CAD). A total of 411 patients (247 males and 164 females; mean age: 61.7 ± 9.9 years) with angiographically proven CAD were included. The patients were divided into 2 groups according to the median MPV value (MPVlow group <9.5 fL and MPVhigh group ≥9.5 fL). The SYNTAX score, high sensitive C-reactive protein (hsCRP) levels, and frequencies of diabetes and hypertension were higher in MPVhigh group compared to MPVlow group. Aortic distensibility (AD) and platelet count of patients in MPVhigh group were lower than patients in MPVlow group ( P < .05, for all). Multivariate linear regression analysis showed that MPV was independently related with diabetes (β = 0.135, P = .007), hsCRP (β = 0.259, P < .001), platelet count (β = −0.144, P < .001), and AD (β = −0.425, P < .001). High MPV value is independently related to AD, as well as diabetes, hsCRP, and platelet count in patients with stable CAD.

Effects of various doses of aspirin on platelet activity and endothelial function

Although aspirin has become an established medicine for cardiac and cerebrovascular diseases, the optimal dose remains unknown. We evaluated the optimal dose of aspirin on platelet activity and endothelial function by administering 11 healthy male volunteers (32 ± 6 years of age) doses of aspirin that were increased in a stepwise manner (0, 81, 162, 330 and 660 mg/day) every 3 days. Platelet activity was assessed as surface P-selectin expression (%) measured by flow cytometry and the platelet aggregation ratio. Endothelial function in the brachial artery was assessed by measuring flow-mediated dilation (FMD) before and after reactive hyperemia. Platelet aggregation and P-selectin expression were significantly and dose-dependently suppressed (81-660 mg), and the FMD ratio tended to increase from 0 to 162 mg, but decreased significantly at 660 mg. In conclusion, although aspirin suppressed platelet activity and even surface P-selectin expression, higher doses worsened endothelial-mediated arterial dilation.

Home-based resistance training improves arterial stiffness in healthy premenopausal women

The present study investigates the effect of home-based resistance training on arterial stiffness in healthy premenopausal women. Twelve healthy non-smoking and normotensive women who were not actively involved in regular physical exercise (aged 42-55 years) performed home-based resistance training twice weekly for 10 weeks using body weight and light dumbbells. Each training session required approximately 40 min to complete. Arterial stiffness was measured using brachial-ankle pulse wave velocity (baPWV). We also determined serum total cholesterol, HDL cholesterol, glucose, triglyceride, insulin, and adiponectin and calculated the homeostasis model assessment of insulin resistance (HOMA-IR), an index of insulin resistance. After home-based resistance training, baPWV, total cholesterol, LDL cholesterol, insulin, and the HOMA-IR decreased, whereas adiponectin increased (P < 0.05) and levels of HDL cholesterol, glucose, triglyceride, blood pressure, and heart rate remained unaffected. These results suggest that home-based resistance training benefits vascular function in healthy premenopausal women.

Elastic Properties of the Ascending Aorta in Patients with ?-Thalassemia Major

BACKGROUND

Beta-thalassemia major (beta-TM) is a congenital hemolytic disorder characterized by impaired left ventricular and endothelial function. However, elastic properties of the aorta have not been sufficiently investigated in patients with beta-TM. We investigated whether beta-TM is related to impaired ascending aortic elastic properties.

METHODS

We studied 36 patients with beta-TM (age: 15.8 +/- 2.6 years) and 30 age- and sex-matched control subjects by echocardiography. Aortic elastic indexes, aortic strain (%), distensibility (cm(2) dyn(-1) 10(-3)), and stiffness index were calculated from the echocardiographically derived thoracic aortic diameters (mm/m(2)), and the measurement of pulse pressure obtained by cuff sphygmomanometry.

RESULTS

Patients versus control subjects had increased aortic diameters (P < 0.001), lower mean aortic strain (9 +/- 3.6 vs. 14.9 +/- 3.2, P < 0.001) and distensibility (0.6 +/- 0.36 vs. 0.8 +/- 0.2, P < 0.012), and higher mean stiffness index (5.3 +/- 2.4 vs. 2.8 +/- 0.6, P < 0.001). Aortic elastic indexes were significantly associated with ferritin level, while stiffness index was significantly related to platelet count.

CONCLUSION

Elastic properties of ascending aorta are impaired in patients with beta-TM. Impaired functions of aorta may lead to deterioration of left ventricular function.