Platelet oxidative stress as a novel target of cardiovascular risk in frail older people

Effects of Different Solvents on the Total Phenol Content, Total Flavonoid Content, Antioxidant, and Antifungal Activities of Micromeria graeca L. from Middle Atlas of Morocco

Micromeria graeca L. is a dense chemical source of bioactive compounds such as phenolic compounds, which have various health-related properties. The current study aimed to investigate the impact of different extractor solvents on phenol and flavonoid contents, as well as the antioxidant and antifungal activities of different extracts. Initially, three extractor solvents (methanol, ethyl acetate, and water) were used to prepare the Soxhlet extracts, which were then examined for their polyphenolic content, flavonoid content, and antioxidant potential using three complementary assays (DPPH, FRAP, and TAC). The antifungal capacity against the two fungal strains (Candida albicans and Aspergillus niger) was performed using the method of diffusion on disc. The dosage of phytochemical compounds revealed that the highest values were established in water extract with values of 360 ± 22.1 mg GAE/g dry weight plant and 81.3 ± 21.2 mg RE/g dry weight plant for TPC and TFC, respectively. In addition, the strongest antioxidant activity measured by DPPH and FRAP assays was established in water extract with IC50 values of 0.33 ± 0.23 and 0.23 ± 0.12 mg/mL, respectively, while the methanol extract showed the best antioxidant activity as measured by TAC with an IC50 of 483 ± 17.6 mg GAEq/g dry weight plant. The water extract recorded the most important antifungal activity against Candida albicans with an inhibition zone of 16 ± 1.6 mm and MFC = 500 μg/mL, whereas ethyl acetate extract showed the lowest activity against both studied fungi strains. Micromeria graeca L. contains considerable amounts of bioactive contents with high antioxidant and antifungal potentials, which may make it a promising source of antioxidants and natural antifungal agents.

Age-Dependent Surface Receptor Expression Patterns in Immature Versus Mature Platelets in Mouse Models of Regenerative Thrombocytopenia

Aging is a multifaceted process that unfolds at both the individual and cellular levels, resulting in changes in platelet count and platelet reactivity. These alterations are influenced by shifts in platelet production, as well as by various environmental factors that affect circulating platelets. Aging also triggers functional changes in platelets, including a reduction in RNA content and protein production capacity. Older individuals and RNA-rich immature platelets often exhibit hyperactivity, contributing significantly to pathologic conditions such as cardiovascular diseases, sepsis, and thrombosis. However, the impact of aging on surface receptor expression of circulating platelets, particularly whether these effects vary between immature and mature platelets, remains largely unexplored. Thus, we investigated the expression of certain surface and activation receptors on platelets from young and old mice as well as on immature and mature platelets from mouse models of regenerative thrombocytopenia by flow cytometry. Our findings indicate that aged mice show an upregulated expression of the platelet endothelial cell adhesion molecule-1 (CD31), tetraspanin-29 (CD9), and Toll-like receptor 2 (TLR2) compared to their younger counterparts. Interestingly, when comparing immature and mature platelets in both young and old mice, no differences were observed in mature platelets. However, immature platelets from young mice displayed higher surface expression compared to immature platelets from old mice. Additionally, in mouse models of regenerative thrombocytopenia, the majority of receptors were upregulated in immature platelets. These results suggest that distinct surface receptor expressions are increased on platelets from old mice and immature platelets, which may partially explain their heightened activity and contribute to an increased thrombotic risk.

Antiplatelet Effects of Selected Xanthine-Based Adenosine A2A and A2B Receptor Antagonists Determined in Rat Blood

The platelet aggregation inhibitory activity of selected xanthine-based adenosine A2A and A2B receptor antagonists was investigated, and attempts were made to explain the observed effects. The selective A2B receptor antagonist PSB-603 and the A2A receptor antagonist TB-42 inhibited platelet aggregation induced by collagen or ADP. In addition to adenosine receptor blockade, the compounds were found to act as moderately potent non-selective inhibitors of phosphodiesterases (PDEs). TB-42 showed the highest inhibitory activity against PDE3A along with moderate activity against PDE2A and PDE5A. The antiplatelet activity of PSB-603 and TB-42 may be due to inhibition of PDEs, which induces an increase in cAMP and/or cGMP concentrations in platelets. The xanthine-based adenosine receptor antagonists were found to be non-cytotoxic for platelets. Some of the compounds showed anti-oxidative properties reducing lipid peroxidation. These results may provide a basis for the future development of multi-target xanthine derivatives for the treatment of inflammation and atherosclerosis and the prevention of heart infarction and stroke.

Platelet activation: a promoter for psoriasis and its comorbidity, cardiovascular disease

Psoriasis is a chronic inflammatory skin disease with a prevalence of 0.14% to 1.99%. The underlying pathology is mainly driven by the abnormal immune responses including activation of Th1, Th17, Th22 cells and secretion of cytokines. Patients with psoriasis are more likely to develop cardiovascular disease (CVD) which has been well recognized as a comorbidity of psoriasis. As mediators of hemostasis and thromboinflammation, platelets play an important part in CVD. However, less is known about their pathophysiological contribution to psoriasis and psoriasis-associated CVD. A comprehensive understanding of the role of platelet activation in psoriasis might pave the path for more accurate prediction of cardiovascular (CV) risk and provide new strategies for psoriasis management, which alleviates the increased CV burden associated with psoriasis. Here we review the available evidence about the biomarkers and mechanisms of platelet activation in psoriasis and the role of platelet activation in intriguing the common comorbidity, CVD. We further discussed the implications and efficacy of antiplatelet therapies in the treatment of psoriasis and prevention of psoriasis-associated CVD.

Independent association of PCSK9 with platelet reactivity in subjects without statin or antiplatelet agents

Background and aims

Proprotein convertase subtilisin/kexin type 9 (PCSK9) levels could predict cardiovascular event in patients with well-controlled LDL-C levels, suggesting an LDL-independent mechanism of PCSK9 on the cardiovascular system. Accumulating evidence suggests PCSK9 might be associated with increased platelet reactivity. This study aimed to assess the relationship between PCSK9 levels and platelet reactivity in subjects not taking statins or antiplatelet agents.

Methods

A cross-sectional study was conducted to investigate the independent contribution of PCSK9 to platelet activity by controlling for the potential confounding factors. The study population included 89 subjects from a health examination centre who underwent routine annual health check-ups or had an examination before a selective operation. Subjects taking statins or antiplatelet agents were excluded. Adenosine diphosphate (ADP)-induced platelet aggregation was determined by PL-11 platelet analyzer using impedance aggregometry and plasma PCSK9 levels were determined using an ELISA. Serum Lipid profile was assessed by measuring the concentration of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG), with low-density lipoprotein cholesterol (LDL-C) being directly measured using enzymatic techniques. The association between PCSK9 and platelet reactivity was investigated.

Results

The study subjects were composed of 53 males and 36 females with an average age of 55 (±11) years old. The univariate correlation analysis showed significant correlation between ADP-induced maximal aggregation rate (MAR) and PCSK9 (r = 0.55, p < 0.001) as well as TC (r = 0.23, p = 0.028), LDL-C (r = 0.27, p < 0.001), and PLT (r = 0.31, p = 0.005). Being male (41.2% vs. 46.6, p = 0.04) and smoking (37.4 vs. 46.2%, p = 0.016) were associated with lower ADP-induced MAR than being female and non-smoking. However, there is no correlation between PCSK9 and AA-induced platelet maximal aggregation rate (r = 0.17, p = 0.12). Multiple regression analysis suggested that PCSK9 contributed independently to ADP-induced maximal aggregation rate (β = 0.08, p = 0.004) after controlling for the effect of TC, LDL-C, PLT, being male, and smoking.

Conclusions

PCSK9 is positively associated with platelet reactivity, which may partly account for the beneficial effect of PCSK9 inhibition in reducing the risk of major adverse cardiovascular events after acute coronary syndrome (ACS).

Analysis of Scientometric Indicators in Publications Associated with Healthy Aging in the World, Period 2011–2020

Today, the world population is aging at a fast rate. This scenario of the accelerated aging of human populations entails increased concern for healthy aging that is associated with a rise in scientific production related to the topic. In this study, the Scopus database from Elsevier was used, with a final search carried out on 5 January 2022, and various bibliometric indicators were obtained from SciVal. The study was fundamentally intended to characterize, determine trends, and understand the evolution and current state of research on the concept of “healthy aging” in the last decade. We found that there has been proportionally greater and more accelerated growth in the subject with respect to the general productivity of the world and that countries with high life expectancies tend to have made more effort to investigate this topic. The “hottest” research areas were found to be related to the cognitive aspect and the biological mechanisms involved in aging.

Improvement effects of esculetin on the formation and development of atherosclerosis

Atherosclerosis is one of the potential causes of death in patients with cardiovascular disease. With the discovery of new anti atherosclerotic drugs becoming the pursuit of the pharmaceutical industry, natural products have attracted more and more attention because of their unique efficacy in the treatment of atherosclerosis. More and more studies have shown that esculetin, a coumarin mainly found in cortex fraxini, can improve atherosclerosis by participating in cellular antioxidant responses and reducing inflammation related pathogenesis. This paper summarizes the researches of esculetin on anti-atherosclerosis in the past two decades. Esculetin plays an anti atherosclerotic role through reducing blood triglyceride level, preventing the proliferation of vascular smooth muscle cells (VSMC) and the production of matrix metallopeptidase 9 (MMP-9), inhibiting the oxidation of low density lipoprotein (LDL) and the secretion of adhesion factors and chemokines, and increasing the outflow level of high density lipoprotein cholesterol (HDL-C). Esculetin is safe and reliable, easy to be absorbed by the body and can be synthesized in a variety of ways. Although there are still few clinical studies on anti-atherosclerosis, in vivo experiments have proved that esculetin has high bioavailability. From the current research, the anti-atherosclerotic effect of esculetin is positive and encouraging. However, much work remains to be done to clarify the molecular mechanism of esculetin in the treatment of atherosclerosis.

Effects of Baru Almond Oil (Dipteryx alata Vog.) Treatment on Thrombotic Processes, Platelet Aggregation, and Vascular Function in Aorta Arteries

Background: This study assessed the effects of Baru (Dipteryx alata Vog.) almond oil supplementation on vascular function, platelet aggregation, and thrombus formation in aorta arteries of Wistar rats. Methods: Male Wistar rats were allocated into three groups. The control group (n = 6), a Baru group receiving Baru almond oil at 7.2 mL/kg/day (BG 7.2 mL/kg, n = 6), and (iii) a Baru group receiving Baru almond oil at 14.4 mL/kg/day (BG 14.4 mL/kg, n = 6). Baru oil was administered for ten days. Platelet aggregation, thrombus formation, vascular function, and reactive oxygen species production were evaluated at the end of treatment. Results: Baru oil supplementation reduced platelet aggregation (p < 0.05) and the production of the superoxide anion radical in platelets (p < 0.05). Additionally, Baru oil supplementation exerted an antithrombotic effect (p < 0.05) and improved the vascular function of aorta arteries (p < 0.05). Conclusion: The findings showed that Baru oil reduced platelet aggregation, reactive oxygen species production, and improved vascular function, suggesting it to be a functional oil with great potential to act as a novel product for preventing and treating cardiovascular disease.

Reducing indoor relative humidity can improve the circulation and cardiorespiratory health of older people in a cold environment: A field trial conducted in Chongqing, China

The changing climate is one of the most important factors affecting public health. Older people are particularly threatened due to their less efficient immune systems. To evaluate the potential benefits of short-term indoor dehumidification on their circulation and cardiopulmonary health, we conducted a random, cross-over experiment with 36 healthy residents of an aged-care center in Chongqing, China in 2020. Vapor compression dehumidifiers were used over two 48-h periods. At the end of each 48 h, we immediately measured sixteen circulatory system biomarkers of inflammation, coagulation, and oxidative stress; lung function; blood pressure; and heart rate. Indoor temperature and relative humidity were monitored throughout the study period. Linear, mixed-effect models were used to associate health endpoints with indoor relative humidity. This intervention study showed that when the indoor relative humidity decreased from 75% to 45%: (1) the coagulation indicators, sCD40l, and PAI-1, decreased significantly, by 58.82% and 23.50%, respectively; (2) the inflammatory indicators, CRP, IL-6, and TNF-α decreased significantly, by 4.09%, 25.78%, and 10.60%, respectively; (3) PEF, FEV₁ and FVC were increased significantly by 20.08%, 14.54%, and 15.75% respectively. To the best of our knowledge, this is the first study to examine the impact of short-term dehumidification on clinical and biochemical measures of cardiorespiratory health in humid areas, and our study suggests that RH in the dehumidified rooms (46.9 ± 8.7%) may be healthier than that in humid rooms (75.2 ± 7.9%). Humidity may be involved in the development of atherosclerosis by activating oxidative stress and mediating the secretion of inflammatory indicators. At the same time, platelet activation induced by oxidative stress stimulates thrombosis to increase cardiovascular risk in older people. Conclusion: This intervention study shows that in a Chinese city like Chongqing with serious indoor environmental humidity, indoor short-term dehumidification has obvious cardiopulmonary benefits for the healthy elderly.

Efficacy and safety of Chinese herbal for carotid atherosclerosis: A protocol for systematic review and network meta-analysis

BACKGROUND

Carotid atherosclerosis (CAS) can cause acute events such as myocardial infarction and stroke, seriously injuring human health. There are some shortcomings for statins and surgical in the treatment of CAS. Research has proved that Chinese herbal shows its unique advantages with the multichannel and multitarget treatment strategy. As a result, we propose this study to evaluate the efficacy and safety of Chinese herbal in the treatment of CAS.

METHOD

We will retrieve the relevant databases to collect the studies of Chinese herbal treatment of CAS up to July 2021. The retrieval language is limited to Chinese and English. Researchers will be responsible for screening studies and extracting data, and use STATA16.0 and WinBUGS1.4.3 for data analysis. We will conduct a bias risk assessment based on the Cochrane Collaboration's bias risk assessment tool and use the grading of recommendations assessment development and evaluation tool to assess the confidence of cumulative evidence.

RESULTS

The study will evaluate the efficacy and safety of Chinese herbal in the treatment of carotid atherosclerosis.

CONCLUSION

The study will offer more evidence for the treatment of CAS with Chinese herbal and expand the selection range of clinicians.

PROTOCOL REGISTRATION NUMBER

INPLASY2021100112.

Can platelet activation result in increased plasma Aβ levels and contribute to the pathogenesis of Alzheimer's disease?

One of the central lesions in the brain of subjects with Alzheimer's disease (AD) is represented by aggregates of β-amyloid (Aβ), a peptide of 40-42 amino acids derived from the amyloid precursor protein (APP). The reasons why Aβ accumulates in the brain of individuals with sporadic forms of AD are unknown. Platelets are the primary source of circulating APP and, upon activation, can secrete significant amounts of Aβ into the blood which can be actively transported to the brain across the blood-brain barrier and promote amyloid deposition. Increased platelet activity can stimulate platelet adhesion to endothelial cells, trigger the recruitment of leukocytes into the vascular wall and cause perivascular inflammation, which can spread inflammation in the brain. Neuroinflammation is fueled by activated microglial cells and reactive astrocytes that release neurotoxic cytokines and chemokines. Platelet activation is also associated with the progression of carotid artery disease resulting in an increased risk of cerebral hypoperfusion which may also contribute to the AD neurodegenerative process. Platelet activation may thus be a pathophysiological mechanism of AD and for the strong link between AD and cerebrovascular diseases. Interfering with platelet activation may represent a promising potential adjunct therapeutic approach for AD.

Impact of thrombus aspiration in frail STEMI patients

BACKGROUND

Despite primary percutaneous coronary intervention (PPCI) is generally considered the best therapy in older frail adults with ST-segment elevation myocardial infarction (STEMI), the incidence of re-hospitalization for cardiovascular diseases remains significant in these patients.

AIMS

We hypothesized that thrombus aspiration (TA) before PPCI could be a useful treatment for reducing mortality and rehospitalizations in frail patients undergoing PPCI for STEMI.

METHODS

We conducted a study comparing PPCI alone vs TA + PPCI in frail STEMI patients. We examined a cohort of consecutive frail patients aged ≥ 65 years with first STEMI treated with PPCI between February 2008 and July 2015 at the Department of Cardiology of the "Cardarelli" Hospital in Naples, Italy.

RESULTS

The study was completed by 389 patients (PPCI: 195, TA + PPCI: 194). At 1-month follow-up, the rate of death from any cause was 7.0% in patients treated with PPCI alone vs 3.0% in patients treated with TA + PPCI (p 0.036), whereas death from cardiovascular causes was 6.0% in the PPCI group vs 3.0% in the TA + PPCI group (p 0.028). Equally important, the rate of re-hospitalization due to heart failure was 7.5% in the PPCI group vs 4.0% in TA + PPCI group (p 0.025) and the rate of re-hospitalization due to acute coronary syndrome was 10.0% in the PPCI group vs 4.5% in the TA + PPCI group (p 0.016).

CONCLUSION

These results indicate the importance of TA in the treatment of STEMI in a group of high-risk patients such as elderly with frailty.

The Association between Peripheral Blood Cells and the Frailty Syndrome in Patients with Cardiovascular Diseases

Background

Frailty syndrome is characterized by multisystem dysregulation frequently found in older individuals or even in younger patients with chronic disabling diseases such as cardiovascular diseases.

Objective

To determine whether peripheral blood cell count, and its subpopulations, red blood cell and platelets, morphology and different ratios (neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and red blood distribution width-to-platelet ratio) are associated with cardiac frail patients, and through this to improve the prediction of frailty status in patients with cardiovascular diseases.

Methods

An observational, retrospective, cohort study enrolling 179 patients with cardiovascular disease divided into two groups: non-frail group (100 pts) and frail group (79 pts), a cohort detached from the Frail.RO study. The frailty was evaluated based on the Fried criteria; haematological markers, sociodemographic data, and variables related to cardiovascular diseases and comorbidities were also recorded.

Results

Lower lymphocytes, platelet count, and neutrophil-to-lymphocyte ratio were significantly associated with a more severe frailty syndrome. Regarding red blood cells, haemoglobin concentration and red cell distribution width significantly correlated with the severity of the frailty syndrome. Receiver operating characteristic curve analysis for these markers associated with the frailty syndrome revealed an acceptable sensitivity of 66% and specificity of 65% to identify frail individuals. Malnutrition and hypercholesterolemia are relevant predictors for identifying frailty in hospitalized cardiovascular patients.

Conclusion

The evaluation of peripheral blood cell composition routinely measured in clinical practice can represent a valuable, but limited indicator, to diagnose frailty syndrome and eventually, the effects of interventions in frail patients with cardiovascular diseases.

Management of acute coronary syndromes in older adults

Older patients are underrepresented in prospective studies and randomized clinical trials of acute coronary syndromes (ACS). Over the last decade, a few specific trials have been conducted in this population, allowing more evidence-based management. Older adults are a heterogeneous, complex, and high-risk group whose management requires a multidimensional clinical approach beyond coronary anatomic variables. This review focuses on available data informing evidence-based interventional and pharmacological approaches for older adults with ACS, including guideline-directed management. Overall, an invasive approach appears to demonstrate a better benefit-risk ratio compared to a conservative one across the ACS spectrum, even considering patients' clinical complexity and multiple comorbidities. Conversely, more powerful strategies of antithrombotic therapy for secondary prevention have been associated with increased bleeding events and no benefit in terms of mortality reduction. An interdisciplinary evaluation with geriatric assessment should always be considered to achieve a holistic approach and optimize any treatment on the basis of the underlying biological vulnerability.

Differences in the prevention and control of cardiovascular and cerebrovascular diseases

At present, the prevention and control of cardiovascular diseases (CAVDs) has made initial advancements, although the prevention and control of cerebrovascular diseases (CEVDs) has not yet achieved the desired progress. In this paper, we review the prevention and control of CEVDs and CAVDs, and analyze the differences in prevention effects, and the pathological and physiological structures pertaining to CEVDs and CAVDs. Combined with the different effects of low-dose aspirin in the primary prevention of CEVDs and CAVDs by meta-analysis, aspirin plays a more important role in the primary prevention of CAVDs than CEVDs. We recognize the misunderstandings and blind spots concerning prevention and control of CEVDs, which can be summarized as follows: (1) CEVDs and CAVDs can be controlled by the same methods and drugs; (2) considering the same pathological factors for cardiovascular diseases; (3) a lack of understanding of the particularity of CEVDs; (4) a focus on platelets and neglect of cerebrovascular protection. In summary, our research clarifies the differences in the prevention measures and drugs used for CEVDs and CAVDs. Of particular concern is the serious lack of preventive drugs for CEVDs in clinical use. An ideal drug for the prevention of CEVDs should have protective effects on the blood, the vascular endothelium, the blood-brain barrier (BBB), and other related factors. Our review aims to highlight several issues in the current prevention of CEVDs and CAVDs, and to provide an optimized plan for preventive drug discovery.

Relationships Between Age, Frailty, Length of Care Home Residence and Biomarkers of Immunity and Inflammation in Older Care Home Residents in the United Kingdom

Aging is associated with changes to the immune system, collectively termed immunosenescence and inflammageing. However, the relationships among age, frailty, and immune parameters in older people resident in care homes are not well described. We assessed immune and inflammatory parameters in 184 United Kingdom care home residents aged over 65 years and how they relate to age, frailty index, and length of care home residence. Linear regression was used to identify the independent contribution of age, frailty, and length of care home residence to the various immune parameters as dependent variables. Participants had a mean age (±SD) of 85.3 ± 7.5 years, had been residing in the care home for a mean (±SD) of 1.9 ± 2.2 years at the time of study commencement, and 40.7% were severely frail. Length of care home residence and frailty index were correlated but age and frailty index and age and length of care home residence were not significantly correlated. All components of the full blood count, apart from total lymphocytes, were within the reference range; 31% of participants had blood lymphocyte numbers below the lower value of the reference range. Among the components of the full blood count, platelet numbers were positively associated with frailty index. Amongst plasma inflammatory markers, C-reactive protein (CRP), interleukin-1 receptor antagonist (IL-1ra), soluble E-selectin and interferon gamma-induced protein 10 (IP-10) were positively associated with frailty. Plasma soluble vascular cell adhesion molecule 1 (sVCAM-1), IP-10 and tumor necrosis factor receptor II (TNFRII) were positively associated with age. Plasma monocyte chemoattractant protein 1 was positively associated with length of care home residence. Frailty was an independent predictor of platelet numbers, plasma CRP, IL-1ra, IP-10, and sE-selectin. Age was an independent predictor of activated monocytes and plasma IP-10, TNFRII and sVCAM-1. Length of care home residence was an independent predictor of plasma MCP-1. This study concludes that there are independent links between increased frailty and inflammation and between increased age and inflammation amongst older people resident in care homes in the United Kingdom. Since, inflammation is known to contribute to morbidity and mortality in older people, the causes and consequences of inflammation in this population should be further explored.

Platelet Function in Cardiovascular Disease: Activation of Molecules and Activation by Molecules

Globally, one of the major causes of death is the cardiovascular disease (CVD), and platelets play an important role in thrombosis and atherosclerosis that led to death. Platelet activation can be done by different molecules, genes, pathways, and chemokines. Lipids activate platelets by inflammatory factors, and platelets are activated by receptors of peptide hormones, signaling and secreted proteins, microRNAs (miRNAs), and oxidative stress which also affect the platelet activation in older age. In addition, surface molecules on platelets can interact with other cells and chemokines in activated platelets and cause inflammation thrombosis events and CVD. However, these molecules activating platelets or being activated by platelets can be suggested as the markers to predict the clinical outcome of CVD and can be targeted to reduce thrombosis and atherosclerosis. However, hindering these molecules by other factors such as genes and receptors can reduce platelet activation and aggregation and targeting these molecules can control platelet interactions, thrombosis, and CVD. In addition, dual therapy with the receptor blockers and novel drugs results in better management of CVD patients. Overall, our review will emphasize on the molecules involved in the activation of platelets and on the molecules that are activated by platelets in CVD and discuss the molecules that can be blocked or targeted to reduce the thrombosis events and control CVD.

Association of Frailty With Antiplatelet Response Among Elderly Chinese Patients With Coronary Artery Disease Undergoing Percutaneous Coronary Intervention

Frailty has been implicated as a prognostic factor for ischemic cardiovascular diseases. However, the effects of frailty on platelet responses to aspirin and clopidogrel remain under investigation. In this study, we enrolled consecutive elderly patients with coronary artery disease (CAD) who were treated by percutaneous coronary intervention (PCI) to evaluate this association. A total of 264 patients (aged 70-95 years) were included. Patients were divided into 2 groups: a nonfrail (nFR) group and a frail (FR) group according to the Clinical Frailty Scale. Platelet reactivity was assessed with a light transmittance aggregometry method, and arachidonic acid and adenosine diphosphate induced maximum platelet aggregation (AA-MPA/ADP-MPA) were calculated to evaluate the platelet response to aspirin and clopidogrel. The results showed that the AA-MPA and ADP-MPA of the FR group were significantly higher than those in the nFR group (17.49 ± 6.65 vs 15.19 ± 6.33, P < .01; 56.13 ± 10.14 vs 45.45 ± 11.59, P < .01). High on-aspirin platelet response (HAPR) and high on-clopidogrel platelet response (HCPR) were significantly more common in the FR group than in the nFR group (24.67% vs 13.16%, P = .028, 37.33% vs 15.79%, P < .01). According to multivariable regression analyses, frailty was found to be independently associated with AA-MPA (β_coefficient = 1.883, P = .042) and ADP-MPA (β_coefficient = 9.287, P < .001), and it was an independent predictor of HAPR (odds ratio [OR]: 2.696, P < .01) and HCPR (OR: 2.543, P < .01). It was concluded that among elderly patients with CAD undergoing PCI, frailty is an independent predictor of HAPR and HCPR, and the state of frailty is independently associated with the platelet responses to clopidogrel and aspirin.

Older adults with frailty syndrome present an altered platelet function and an increased level of circulating oxidative stress and mitochondrial dysfunction biomarker GDF-15

INTRODUCTION

The elderly population is increasing worldwide and in Chile, it is expected to grow rapidly. The World Health Organization (WHO) ICOPE guideline (Integrated Care for Older People) emphasizes the importance of frailty diagnosis to prevent dependence. Frailty in older adults is considered an indicator of vulnerability and poor health outcomes, of multifactorial etiology. Our objective was to investigate the association of activation of coagulation and increased risk of thrombosis with frailty in people older than 64 years. A prevalent-case control study was designed with 28 frail older and 27 robust older adults (non-frail, control group) older than 64 years. Frailty was defined by Fried's Phenotype, Platelet aggregation and activation plasma levels of Thromboxane B2 (TXB2), 8-isoprostane and Growth Differentiation Factor-15 (GDF-15) were determined.

RESULTS

Compared to healthy controls, frail older adults, had a) higher percentage of platelet aggregation induction with ADP 4 μM (82.85% (3.35) and 73.41% (3.26), p-value = 0.024) and subaggregant dose of ADP (30.83% (7.47) and 13.25% (3.21), p-value = 0.002); b) higher platelet activation: P-selectin exposure (18.23% (4.41) and 6.96% (1.08), p-value = 0.011), and activated GPIIβ-IIIα (21.51% (3.41) and 8.26% (1.18), p-value = 0.001), at the baseline level and against a subaggregant dose ADP: P-selectin exposure (46.93% (5.95) and 13.41% (3.35), p-value = 0.002) and activated GPIIβ-IIIα (43.29% (6.04) and 26.71% (4.92), p-value = 0.024); c) higher plasma levels of TXB2 (201.8 ng/mL (59.53-236.3) and 45.77 ng/mL (25.14-98.26), p-value<0.0001), d) elevated plasma levels of 8-isoprostane (70.94 pg/mL, IQ: 65.89-99,96 and 56.24 pg/mL, IQ: 42.18-74.81, p-value = 0.001), and e) higher plasma GDF-15 levels (2,379 pg/mL, IQ: 1,845-4,121and 1367 pg/mL, IQ: 1190-1747, p-value = 0.0001).

DISCUSSION

Older adults with frailty syndrome have an upregulated platelet activity that may contribute to an increased risk of thrombosis and aspirin resistance. The elevated oxidative stress and increases of GDF-15 levels might be related to altered platelet responsiveness in frail patients.

CONCLUSION

The determination of biomarkers of platelet dysfunction, oxidative stress and cell senescence/mitochondrial dysfunction may contribute to frailty diagnosis, and approaches aimed at regulating platelet function in frail older adults could contribute to its prevention and treatment.

Platelet Function in Aging

Aging is associated with an increased incidence of cardiovascular disease and thrombosis. Platelets play a major role in maintaining hemostasis and in thrombus formation, making them a key player in thrombotic disorders. Whereas it is well-known that platelet aggregability is increased in vascular diseases, the contribution of age-related changes in platelet biology to cardiovascular risk is not well-understood. Several lines of evidence support that platelets from older subjects differ in their function and structure, making platelets more prone to activation and less sensitive to inhibition. These age-related changes could lead to platelet hyperactivity and to the development of a prothrombotic state in advanced age. This review will focus on platelet biochemical modifications during aging and on the mechanisms by which these alterations could lead to thrombotic disease.

Age associated non-linear regulation of redox homeostasis in the anucleate platelet: Implications for CVD risk patients

Background

Aging is a complex physiological phenomenon, intricately associated with cardiovascular pathologies, where platelets play a central pathophysiological role. Although antiplatelets are commonly employed to prevent and treat major adverse cardiovascular events, aging associated intraplatelet changes remain largely unexplored.

Methods

Platelets were studied in high cardiovascular risk patients (aged 40–100 years) comparing them to younger healthy subjects. This was followed by cross sectional and longitudinal mice studies. Flow cytometry, biochemical and molecular assays were used to study platelets comprehensively.

Findings

CVD Patients were categorized in the age groups 40–59, 60–79, and 80–100 years. Progressive decline in platelet health was observed in the 40–79 years age cohort, marked by increase in oxidative stress, hyperactivation and apoptotic markers. Paradoxically, this was reversed in patients aged above 79 years and the improved platelet phenotype was associated with lower oxidative damage. The platelets from the very old (80–100 year) group were found to be preloaded with increased antioxidants, which also contributed to higher resistance against induced redox insults. Cross sectional mouse studies excluded the effect of comorbidities and medications. Longitudinal mouse studies implicate an adaptive increase in antioxidant levels as the mechanism.

Interpretation

We report a novel age associated, non-linear redox regulation in platelets in both humans and mice. In advanced age, there occurs an adaptive increase in platelet antioxidants, reducing the intracellular ROS and leading to a healthier platelet phenotype. Clinically, our results advocate the use of less aggressive antiplatelet therapies for CVD in the elderly population.

Fund

Study funded by NIH-NHLBI, RO1-HL122815 and RO1-HL115247.

Oxidative stress in biological systems and its relation with pathophysiological functions: the effect of physical activity on cellular redox homeostasis

The body of evidence from the past three decades demonstrates that oxidative stress can be involved in several diseases. This study aims to summarise the current state of knowledge on the association between oxidative stress and the pathogenesis of some characteristic to the biological systems diseases and aging process. This review also presents the effect of physical activity on redox homeostasis. There is strong evidence from studies for participation of reactive oxygen and nitrogen species in pathogenesis of acute and chronic diseases based on animal models and human studies. Elevated levels of pro-oxidants and various markers of the oxidative stress and cells and tissues damage linked with pathogenesis of cancer, atherosclerosis, neurodegenerative diseases hypertension, diabetes mellitus, cardiovascular disease, atherosclerosis, reproductive system diseases, and aging were reported. Evidence confirmed that inflammation contributes widely to multiple chronic diseases and is closely linked with oxidative stress. Regular moderate physical activity regulates oxidative stress enhancing cellular antioxidant defence mechanisms, whereas acute exercise not preceded by training can alter cellular redox homeostasis towards higher level of oxidative stress. Future studies are needed to clarify the multifaceted effects of reactive oxygen/nitrogen species on cells and tissues and to continue study on the biochemical roles of antioxidants and physical activity in prevention of oxidative stress-related tissue injury.