Altered dynamics of calcium fluxes and mitochondrial metabolism in platelet activation-related disease and aging.

Understanding the mechanisms controlling platelet function is crucial for exploring potential therapeutic targets related to atherothrombotic pathologies and primary hemostasis disorders. Our research, which focuses on the role of platelet mitochondria and Ca2+ fluxes in platelet activation, the formation of the procoagulant phenotype, and thrombosis, has significant implications for the development of new therapeutic strategies. Traditionally, Ca2+-dependent cellular signaling has been recognized as a determinant process throughout the platelet activation, controlled primarily by store-operated Ca2+ entry and the PLC-PKC signaling pathway. However, despite the accumulated knowledge of these regulatory mechanisms, the effectiveness of therapy based on various commonly used antiplatelet drugs (such as acetylsalicylic acid and clopidogrel, among others) has faced challenges due to bleeding risks and reduced efficacy associated with the phenomenon of high platelet reactivity. Recent evidence suggests that platelet mitochondria could play a fundamental role in these aspects through Ca2+-dependent mechanisms linked to apoptosis and forming a procoagulant phenotype. In this context, the present review describes the latest advances regarding the role of platelet mitochondria and Ca2+ fluxes in platelet activation, the formation of the procoagulant phenotype, and thrombosis.

Regulation of mitochondrial function by hydroquinone derivatives as prevention of platelet activation.

Platelet activation plays an essential role in the pathogenesis of thrombotic events in different diseases (e.g., cancer, type 2 diabetes, Alzheimer's, and cardiovascular diseases, and even in patients diagnosed with coronavirus disease 2019). Therefore, antiplatelet therapy is essential to reduce thrombus formation. However, the utility of current antiplatelet drugs is limited. Therefore, identifying novel antiplatelet compounds is very important in developing new drugs. In this context, the involvement of mitochondrial function as an efficient energy source required for platelet activation is currently accepted; however, its contribution as an antiplatelet target still has little been exploited. Regarding this, the intramolecular hydrogen bonding of hydroquinone derivatives has been described as a structural motif that allows the reach of small molecules at mitochondria, which can exert antiplatelet activity, among others. In this review, we describe the role of mitochondrial function in platelet activation and how hydroquinone derivatives exert antiplatelet activity through mitochondrial regulation.

Frailty in Aging and the Search for the Optimal Biomarker: A Review.

In the context of accelerated aging of the population worldwide, frailty has emerged as one of the main risk factors that can lead to loss of self-sufficiency in older people. This syndrome is defined as a reduced state of physiological reserve and functional capacity. The main diagnostic tools for frailty are based on scales that show deficits compared to their clinical application, such as the Fried frailty phenotype, among others. In this context, it is important to have one or more biomarkers with clinical applicability that can objectively and precisely determine the degree or risk of frailty in older people. The objective of this review was to analyze the biomarkers associated with frailty, classified according to the pathophysiological components of this syndrome (inflammation, coagulation, antioxidants, and liver function, among others). The evidence demonstrates that biomarkers associated with inflammation, oxidative stress, skeletal/cardiac muscle function, and platelet function represent the most promising markers of frailty due to their pathophysiological association with this syndrome. To a lesser extent but with the possibility of greater innovation, biomarkers associated with growth factors, vitamins, amino acids, and miRNAs represent alternatives as markers of this geriatric syndrome. Likewise, the incorporation of artificial intelligence represents an interesting approach to strengthening the diagnosis of frailty by biomarkers.

Characterization by Gender of Frailty Syndrome in Elderly People according to Frail Trait Scale and Fried Frailty Phenotype.

Background: Frailty has emerged as one of the main geriatric syndromes to be prevented in order to improve quality of health and life in the elderly. In this sense, the characterization of this syndrome through reliable and feasible diagnostic tools for clinical use, such as the Frail Trait Scale 5 (FTS-5) and Frail Trait Scale 3 (FTS-3), represents the basis for this objective. Objectives: To characterize the frailty syndrome in a population of older adults using FTS-5, FTS-3, and Fried phenotype (FP) as frailty diagnostic tools. Design: Cross-sectional study. Participants: 300 adults ≥65 years recruited from different Family Health Centers and community groups of older people in Talca, Chile. Methods: The diagnosis of frailty was made according to FP, FTS-5, and FTS-3 tools. Data about sociodemographic characteristics and anthropometric measurements were collected by a clinical interview by a previously trained health professional. Results: A total prevalence of frailty according to the FP of 19.7% was observed; while in the group of women and men it was 21.4% and 15.0%, respectively. Concerning the FTS-5 tool, the total prevalence of frailty was 18%, while in the group of women and men was 18.0% and 17.5%, respectively. The FTS-3 tool shows a total prevalence of frailty of 23.3%, while in the group of women and men a prevalence of 22.7% and 25.0%, respectively. A significant difference is observed with respect to the presence of the Fried criteria of "weakness" (women: 21.4%, men: 38.8%) and "weight loss" (women: 16.8%, men: 7.5%; p < 0.05). A significant difference is observed concerning the average score of "Handgrip" criteria, "walking time", and "Physical Activity Scale for the Elderly" (PASE) between the group of women and men. Frailty, diagnosed by FTS-3, is significantly associated with the risk factors of overweight (body mass index ≥ 25) (OR: 10.225, 95% CI: 1.297−80.617) and advanced age (age ≥ 75 years) (OR: 1.839, 95% CI: 1.040−3.250). Conclusion: The prevalence of frailty observed with the FTS-5 (18%) and FTS-3 (23.3%) tools are similar to the prevalence observed through the FP (19.7%) and those reported in other observational studies. Considering the similar prevalence of frailty diagnosed with the three tools, FTS-3 should be a valuable tool for the screening of frailty in the community.

The Role of Coffee and its Bioactive Components in Platelet Function and Aging.

Cardiovascular diseases (CVD) are known to be the world's leading cause of death and different factors are known to increase the risk of death, including aging, mainly due to increased oxidative stress and inflammation observed in older people. Acute myocardial infarctions and cerebrovascular accidents belong to CVD, and are the ones that cause the most deaths and disabilities, where greater platelet activation plays an important role in pathophysiology. These diseases are more prevalent in older people, which have a clear relationship with increased platelet function and are strongly related to aging. Platelet function is affected by diet, which varies in its requirements and characteristics according to age. Coffee belongs to the family of diet elements that can alter platelet function and an increase in coffee consumption with advancing age, and a U-shaped correlation with the risk of CVD have been reported. However, the effect of coffee consumption and its bioactive compounds on platelet function and aging presents controversial evidence, and therefore, a complex effect is not fully elucidated in the cardiovascular system. This review focuses on the relationship between coffee consumption (and its constituent bioactive compounds), and platelet function, and aging.

Plasma Vitamin C and Risk of Late Graft Failure in Kidney Transplant Recipients: Results of the TransplantLines Biobank and Cohort Study.

Recent studies have shown that depletion of vitamin C is frequent in outpatient kidney transplant recipients (KTR) and that vitamin C is inversely associated with risk of death. Whether plasma vitamin C is associated with death-censored kidney graft failure remains unknown. We investigated KTR who participated in the TransplantLines Insulin Resistance and Inflammation Biobank and Cohort Study. The primary outcome was graft failure (restart of dialysis or re-transplantation). Overall and stratified (pinteraction < 0.1) multivariable-adjusted Cox regression analyses are presented here. Among 598 KTR (age 51 ± 12 years-old; 55% males), baseline median (IQR) plasma vitamin C was 44.0 (31.0-55.3) µmol/L. Through a median follow-up of 9.5 (IQR, 6.3‒10.2) years, 75 KTR developed graft failure (34, 26, and 15 events over increasing tertiles of vitamin C, log-rank p < 0.001). Plasma vitamin C was inversely associated with risk of graft failure (HR per 1-SD increment, 0.69; 95% CI 0.54-0.89; p = 0.004), particularly among KTR with triglycerides ≥1.9 mmol/L (HR 0.46; 95% CI 0.30-0.70; p < 0.001; pinteraction = 0.01) and among KTR with HDL cholesterol ≥0.91 mmol/L (HR 0.56; 95% CI 0.38-0.84; p = 0.01; pinteraction = 0.04). These findings remained materially unchanged in multivariable-adjusted analyses (donor, recipient, and transplant characteristics, including estimated glomerular filtration rate and proteinuria), were consistent in categorical analyses according to tertiles of plasma vitamin C, and robust after exclusion of outliers. Plasma vitamin C in outpatient KTR is inversely associated with risk of late graft failure. Whether plasma vitamin C‒targeted therapeutic strategies represent novel opportunities to ease important burden of graft failure necessitates further studies.

Latest Advances in Hydrogel-Based Drug Delivery Systems for Optimization of Metabolic Syndrome Treatment.

BACKGROUND: Drug delivery systems such as hydrogels have become relevant in cardiovascular and metabolic therapies due to their sustained and controlled release properties of drugs, versatile polymer structures, safety, and biodegradability. RESULTS: The literature presented demonstrates that a hydrogel-based controlled release system increases the therapeutic efficacy in different components of the metabolic syndrome. Hypertension has been the most explored component with advances in in vitro and murine models. However, clinical evidence in humans is scarce, and more translational studies are needed. Hydrogel-based systems for diabetes, obesity, and dyslipidemia have been little explored. Observations mainly demonstrated an increase in therapeutic efficacy, in vitro and in vivo, for the use of insulin, leptin, and natural components, such as epigallocatechin gallate. In all cases, the hydrogel systems achieve better plasma levels of the loaded compound, higher bioavailability, and low cytotoxicity compared to conventional systems. Also, the evidence existing suggests that the development of an injectable hydrogel system for controlled release of drugs or therapeutic compounds is presented as an attractive option for MeS treatment, and due to the possibility of sustained pharmacological release, there is no need for repeated doses and a safe administration route. CONCLUSION: The following review aims to evaluate the use of the hydrogel systems in the therapy of diabetes, obesity, hypertension, and dyslipidemia, which are the main components of metabolic syndrome.

Frail older adults show a distinct plasma microvesicle profile suggesting a prothrombotic and proinflammatory phenotype.

In a global context of advanced aging, geriatric diseases such as frailty syndrome face challenges in the search for biomarkers and preventive strategies. Frailty has been associated with atherothrombotic pathologies. Circulating microvesicles (cMVs), phospholipid-rich vesicles with a size of 0.1-1.0 µm, have been shown to participate in atherothrombosis onset and progression. We have hypothesized that cMVs from platelets, and vascular and immune cells, are increased in frail older adults. To verify this, a prevalent-case control study was designed with 28 frail older and 27 nonfrail older adults older than 64 years. Frailty was defined by Fried's phenotype. Total cMVs, annexin V positive (AV+)-cMVs, and annexin V negative (AV- )-cMVs derived from blood and vascular cells were measured by flow cytometry. In the analysis of total cMVs, the frail group presented higher levels of CD14+ /CD142+ (p = .042), CD41a+ /CD142+ (p = .041), and CD56+ (p = .025), CD14+ cMVs (p = .043), and CD16+ /CD14+ (p = .019) cMVs levels. Within the phosphatidylserine-exposing cMVs (AV+ ), the frail group showed higher CD14+ /AV+ (p = .044), CD9+ /AV+ (p = .031), P2RY12+ /AV+ (p = .028), and CD235a+ /AV+ (p = .043) cMVs concentrations. Finally, within AV- cMVs, the frail group showed higher CD142+ /CD41a+ /AV- cMVs concentrations originated from platelets (p = .027), CD56+ /AV- originated from natural killer cells (p = .022), and CD34+ /AV- cMVs from hematopoietic stem cells (p = .037). In summary, frail older adults present higher concentrations of platelet-, leukocyte-, and hematopoietic cell-derived cMVs compared to robust age-matched older adults. These cMVs may be involved in the deregulation of the immune system, endothelial damage, and increased risk of thrombosis associated with frailty.

Mitoquinone (MitoQ) Inhibits Platelet Activation Steps by Reducing ROS Levels.

Platelet activation plays a key role in cardiovascular diseases. The generation of mitochondrial reactive oxygen species (ROS) has been described as a critical step required for platelet activation. For this reason, it is necessary to find new molecules with antiplatelet activity and identify their mechanisms of action. Mitoquinone (MitoQ) is a mitochondria-targeted antioxidant that reduces mitochondrial overproduction of ROS. In this work, the antiplatelet effect of MitoQ through platelet adhesion and spreading, secretion, and aggregation was evaluated. Thus MitoQ, in a non-toxic effect, decreased platelet adhesion and spreading on collagen surface, and expression of P-selectin and CD63, and inhibited platelet aggregation induced by collagen, convulxin, thrombin receptor activator peptide-6 (TRAP-6), and phorbol 12-myristate 13-acetate (PMA). As an antiplatelet mechanism, we showed that MitoQ produced mitochondrial depolarization and decreased ATP secretion. Additionally, in platelets stimulated with antimycin A and collagen MitoQ significantly decreased ROS production. Our findings showed, for the first time, an antiplatelet effect of MitoQ that is probably associated with its mitochondrial antioxidant effect.

Polypharmacy Is Associated with Frailty, Nutritional Risk and Chronic Disease in Chilean Older Adults: Remarks from PIEI-ES Study.

AIM: To analyze the relationship between polypharmacy and variables as frailty and other chronic comorbidities in Chilean older adults. DESIGN: Cross-sectional study. PARTICIPANTS: One thousand two hundred and five older adults aged 65 and older. METHODS: The presence or absence of frailty syndrome was determined according to Fried criteria. Data collection was made through questionnaires conducted by an interview. RESULTS: The prevalence of polypharmacy was 37.59%. The prevalence of hyperpolypharmacy was 2%. Increased prevalence of frailty was demonstrated regarding the progression of the state of polypharmacy. When analyzing the contribution of frailty respect polypharmacy condition, frail state, nutritional risk and obesity are founded as a factor associated with polypharmacy. Regarding chronic disease, hypertension (OR: 8.039, p<0.0001), type 2 diabetes (OR: 4.001, p<0.0001) and respiratory diseases (OR: 2.930, p<0.0001) were associated to polypharmacy. It was found a strong and significant positive correlation between polypharmacy prevalence and frailty score (polypharmacy condition, Spearman R: 0.89, p=0.033; hyperpolypharmacy condition, Spearman R: 0.94, p=0.016). When analyzing the contribution of the polypharmacy to the presence of frailty, polypharmacy condition (OR: 1.510, p<0.05), cognitive impairment (OR: 3.887, p<0.001), obesity (OR: 1.560, p<0.01) and nutritional risk (OR: 2.590, p<0.001) are associated to frailty. CONCLUSION: Frailty and chronic conditions as nutritional risk, obesity, hypertension, type 2 diabetes and respiratory disease are an important risk factor for the development of polypharmacy in Chilean older adults. Likewise, polypharmacy condition was observed to be a risk factor for frailty, demonstrating the bidirectional relationship between both conditions. Frailty syndrome evaluation in Chilean older adults could be an important alternative for polypharmacy prevention.

Effects of frailty status on happiness and life satisfaction: The mediating role of self-perceived health / Efectos del estado de fragilidad en la felicidad y la satisfacción con la vida: el papel mediador de la salud autopercibida

Abstract During the past decade, the frail syndrome has acquired great importance due to its detrimental social and psychological consequences. In the present study, we investigate the association between frailty status and well-being (happiness and life satisfaction) among older adults, and we test the role of self-perceived health as potential mediator in such relations. We recruited 1205 older Chilean adults who responded to measures about their objective health status (frailtyrelated indicators), well-being, and self-perceived health. Overall, path analyses showed that frailty status is negatively associated to life satisfaction and happiness, and that self-perceived health works as a mediator for such relations. The social and psychological consequences of the frail syndrome in older adults are discussed.

Resumen: Durante la última década, el síndrome de fragilidad ha adquirido gran importancia debido a sus consecuencias sociales y psicológicas perjudiciales. En el presente estudio, investigamos la asociación entre el estado de fragilidad y el bienestar (felicidad y satisfacción con la vida) en los adultos mayores, y evaluamos el papel de la salud autopercibida como potencial mediador de dichas relaciones. Reclutamos a 1205 adultos mayores chilenos que respondieron preguntas acerca de su estado de salud objetivo (indicadores relacionados con el estado de fragilidad), bienestar y autopercepción de salud. En términos generales, los análisis mostraron que el estado de fragilidad se asocia negativamente con la satisfacción vital y la felicidad, y que la salud autopercibida tiene un papel mediador en tales relaciones. Se discuten las consecuencias sociales y psicológicas del síndrome de fragilidad en adultos mayores.

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 GPIIß-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 GPIIß-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.

Natural Bioactive Compounds As Protectors Of Mitochondrial Dysfunction In Cardiovascular Diseases And Aging.

Diet, particularly the Mediterranean diet, has been considered as a protective factor against the development of cardiovascular diseases, the main cause of death in the world. Aging is one of the major risk factors for cardiovascular diseases, which have an oxidative pathophysiological component, being the mitochondria one of the key organelles in the regulation of oxidative stress. Certain natural bioactive compounds have the ability to regulate oxidative phosphorylation, the production of reactive oxygen species and the expression of mitochondrial proteins; but their efficacy within the mitochondrial physiopathology of cardiovascular diseases has not been clarified yet. The following review has the purpose of evaluating several natural compounds with evidence of mitochondrial effect in cardiovascular disease models, ascertaining the main cellular mechanisms and their potential use as functional foods for prevention of cardiovascular disease and healthy aging.

High-Intensity Exercise Reduces Cardiac Fibrosis and Hypertrophy but Does Not Restore the Nitroso-Redox Imbalance in Diabetic Cardiomyopathy.

Diabetic cardiomyopathy refers to the manifestations in the heart as a result of altered glucose homeostasis, reflected as fibrosis, cellular hypertrophy, increased oxidative stress, and apoptosis, leading to ventricular dysfunction. Since physical exercise has been indicated as cardioprotective, we tested the hypothesis that high-intensity exercise training could reverse the cardiac maladaptations produced by diabetes. For this, diabetes was induced in rats by a single dose of alloxan. Diabetic rats were randomly assigned to a sedentary group or submitted to a program of exercise on a treadmill for 4 weeks at 80% of maximal performance. Another group of normoglycemic rats was used as control. Diabetic rat hearts presented cardiomyocyte hypertrophy and interstitial fibrosis. Chronic exercise reduced both parameters but increased apoptosis. Diabetes increased the myocardial levels of the mRNA and proteins of NADPH oxidases NOX2 and NOX4. These altered levels were not reduced by exercise. Diabetes also increased the level of uncoupled endothelial nitric oxide synthase (eNOS) that was not reversed by exercise. Finally, diabetic rats showed a lower degree of phosphorylated phospholamban and reduced levels of SERCA2 that were not restored by high-intensity exercise. These results suggest that high-intensity chronic exercise was able to reverse remodeling in the diabetic heart but was unable to restore the nitroso-redox imbalance imposed by diabetes.

Simplified HPLC methodology for quantifying biological pterins by selective oxidation.

Tetrahydrobiopterin (BH4) has become a potential therapeutic tool to treat cardiovascular diseases, since it is an essential cofactor of nitric oxide synthase. In order to quantify the amount of BH4 and its related biopterins, a procedure that involves differential oxidation is currently used, which measures biopterin (the product of the oxidation of BH4 and BH2) at two different pH conditions to calculate the quantity of BH2 and BH4, using high performance liquid chromatography (HPLC). In this work, a method was established in order to quantify BH4 and BH2 by adapting previously described procedures. Several chromatographic conditions were evaluated to define the most convenient methodology. Four types of mobile phases and two different analytical columns were used for HPLC. Additionally, calibration curves were made in acid and basic pH compatible with the differential oxidation method. Each method was suitable for quantification purposes, but the choice was based on an economic factor. The selected condition was a mobile phase of 95% water/5% methanol using a C18 column at 35°C at a flow rate of 0.9mL/min. Then, it was calculated the recovery rate, which was about 80% using the chosen method. The aim of this work was to establish a simplified method of differential oxidation, compatible with matrixes such as cardiac tissue in order to facilitate the assessment of the BH4/BH2 ratio in biological samples.