Clinical Research Directory

Samples From Human Subjects to Facilitate Basic, Translational and Clinical Research

Background: This study is designed to provide samples to help us study the genes your blood cells are making as well as the proteins, sugars, fats, vitamins and other metabolites found in your blood or urine. Blood samples may also be collected to make special cells. These are called induced pluripotent stem cells or iPSCs. Pluripotent stem cells are cells that can be converted into any type of cell. Researchers want to study in the lab iPSCs that are derived from blood samples. Objective: To collect samples to help study genes, proteins, sugars, fats, vitamins, and other metabolites found in blood or urine. Eligibility: Healthy volunteers and patients ages 18 and older Design: First-time research study participants at NIH will have an initial visit for this study that should last no more than 1 hour. All other visits should last 20 30 minutes. Participants will undergo a limited history and physical exam. Participants may have routine blood and urine tests. If participants are giving a blood sample, they must have a hemoglobin level checked in the past 12 months to make sure it is safe for them to give a blood sample for research. Participants may have a venous blood collection. They may do this at several visits. They will lie on a recliner or couch or sit in a chair. A needle will be placed into a vein in the hand or arm, using sterile techniques. Blood will be withdrawn into multiple syringes or tubes. Participants may be asked to provide urine in an appropriate container...

Impact of the Mandibular Advancement Device on Sleep Apnea During CPAP Withdrawal

Obstructive sleep apnea hypopnea syndrome (OSAS) is a frequent disease with neuropsychological and cardiovascular (CV) consequences. Continuous positive pressure (CPAP), the main treatment for OSAHS, is effective on the majority of symptoms but restrictive, which can promote non-compliance. Treatment interruptions are often observed in connection with intercurrent events such as nasal obstructions or even when patients are on the move. However, randomized trials have shown that stopping treatment, even for a short time, leads to a recurrence of symptoms and significant CV disturbances (increase in blood pressure, endothelial dysfunction, cardiac repolarization disorders). It seems important to consider strategies that promote therapeutic continuity. The mandibular advancement device (MAD) is an interesting tool in this regard. MAD is as effective as CPAP on symptoms and CV data. The investigators want to assess its effectiveness as a complementary treatment during treatment discontinuation on the main consequences of OSAHS.

TB-500 (Thymosin Beta 4 17-23 Fragment) for Cardiovascular Biomarkers in Stable ASCVD

This fictional study is an example of a ClinicalTrials.gov-style record. It describes a Phase 1/2 trial evaluating the safety and tolerability of TB-500 (a 17-23 fragment of thymosin beta 4) versus placebo in adults with stable atherosclerotic cardiovascular disease (ASCVD). Exploratory endpoints assess vascular function and inflammation biomarkers

Associations Between Dietary Patterns, LDL Aggregation, and Cardiometabolic Health: A Cross-sectional Analysis.

This study aims to investigate the extent to which vegan or plant-based, omnivorous, and carnivore dietary patterns affect LDL aggregation susceptibility (the affinity for LDL cholesterol particles to clump together in the blood), which may promote plaque build-up in arteries. Using a cross-sectional mixed-methods design, the study will measure LDL aggregation, blood lipids, and other metabolic biomarkers in individuals following these diets, and combine these data with dietary and behavioural information to examine links with cardiovascular and metabolic health.

TRIal of STatin Therapy Effect on Androgen Status and Erectile functioN in Men

Aim. To study the effect of different intensities of statin therapy on androgen status and erectile function in men aged 40-65 years with high and very high cardiovascular risk. Additionally, to assess the association between sex hormone levels, erectile function parameters, and traditional cardiovascular risk factors, arterial stiffness, and endothelial function in this patient category. Material and methods. It is planned to conduct a prospective randomized controlled trial, including 150 male patients aged 40-65 years, undergoing routine preventive examinations in the clinic of Moscow State University, having a high and very high risk of cardiovascular diseases and meeting the inclusion criteria. Group Pit (n=75) will receive pitavastatin at a starting dose of 1 mg/day. Group Ros (n=75) will receive rosuvastatin 20 mg/day. After 3 months, the biochemical parameters will be monitored, and dose titration of pitavastatin to 2-4 mg/day and/or rosuvastatin to 40 mg/day will be performed if necessary. Patient recruitment to the study will occur over 9 months at a single research center. Patients will be monitored with an objective assessment of erectile function parameters, blood analysis (including androgen status), central arteries stiffness, and endothelial function for 6 months from the moment of activation. Follow-up visits are scheduled at 1, 3 and 6 months. Results. The expected result of testing the research hypothesis is that statin therapy will not have a negative effect on androgen status and erectile function in men. Intensive statin therapy will have a greater positive effect on endothelial function, which may lead to an improvement in men's erectile function. Conclusion. The study was planned under the assumption that statin therapy would not have a negative effect on androgen status and erectile function in men aged 40-65 years. It is also suggested that the positive effect of statins on endothelial function and vascular stiffness may lead to an improvement in erectile function among men with high and very high cardiovascular risk. If the hypothesis is confirmed, the results obtained will help improve statin treatment adherence in male patients and, as a result, increase the effectiveness of prevention of cardiovascular events.

Effect of a Daily Supplement on Plasma PAI-1 Levels

In a healthy person, the production of nitric oxide (NO) by the endothelium, the inner lining of the blood vessel, is responsible for a) the ability of the blood vessel to dilate so it can increase its blood flow and b) act as an anti-clotting product to prevent blood clotting in those vessels. Under physiological stress either due to the development of a disease such as diabetes or simply from aging, the endothelial cells can be impacted and become dysfunctional, thereby impairing their ability to make NO and even promoting the development of blood clots. When such endothelial dysfunction occurs, it may be a precursor for the future development of cardiovascular (CV) disease like hypertension or coronary artery disease later on in life in these patients. Therefore, the ability to enhance the local production or availability of NO within such affected blood vessels in patients identified as prone to endothelial dysfunction could play a positive role in either preventing or delaying the onset of endothelial dysfunction and subsequent CV disease in such patients. RM is an oral supplement consisting of natural ingredients and the amino acid, L-citrulline. In laboratory experiments with cells from the inner lining of blood vessels, the four components of RM have been shown to increase the concentration of NO and decrease the levels of some aging markers. In our recently completed study (manuscript currently in review), 31 young men and women took the supplement for 14 days and had no serious side effects. The supplement caused the expected potentially beneficial dilation of the blood vessels and decrease in the levels of Plasminogen Activator Inhibitor-1 (PAI-1), whose levels correlate with aging and risk of cardiovascular disease. In this study, healthy participants will consume the supplement for a 6-week period to determine if PAI-1 levels continue to be suppressed and also examine whether the supplement has an effect on other blood markers whose levels can change with aging or cardiovascular disease and may also be indicative or predictive of an illness.

Enhancing Parasympathetic Activity to Improve Endothelial Dysfunction, Vascular Oxidative Stress in African Americans

Specific Aim 1: To test the hypothesis that prolonged (3-month) treatment with galantamine inhibits NADPH IsoLG-protein adducts formation and improves markers of endothelial cell (EC) dysfunction in AAs. Aim 1a: The investigators will determine if galantamine inhibits NADPH IsoLG-protein adducts formation, superoxide production, and immune cell activation compared to placebo. For this purpose, the investigators will study peripheral blood mononuclear cell (PBMC), a critical source of systemic oxidative stress, collected from study participants. Aim 1b: The investigators will determine if galantamine reduces intracellular Iso-LGs, ICAM-1, and 3-nitrotyrosine, a marker of vascular oxidative stress, in ECs harvested from study participants. Specific Aim 2: To determine if prolonged (3-month) treatment with galantamine improves endothelial dysfunction as measured by vascular reactivity in AAs. The investigators will measure vascular reactivity in response to ischemia in two vascular beds: (a) in conduit arteries (brachial artery) using brachial artery diameter flow-mediated dilation (FMD), and (b) in the microvasculature (MBV) using contrast-enhanced ultrasonography in skeletal muscle. Sub-study (optional) Will study the effect of trans-auricular vagus nerve stimulation (TaVNS) during a period of enhanced vascular oxidative stress This proposal will study a novel mechanism that could alter the oxidative and immunogenic responses that contributes to endothelial dysfunction in AAs and will offer a potential pathway for the development of more effective therapies aimed at decreasing the progression of endothelial dysfunction to cardiovascular disease in this population.

The Effect of Lipoprotein (a) on Arterial Stiffness, Endothelial Function and Myocardial Deformation

1. Introduction Lipoprotein(a), or Lp(a), is a type of lipoprotein that is structurally similar to LDL (low-density lipoprotein) but carries an additional protein called apolipoprotein (a). 2. Purpose of the Study The primary purpose of this study is to investigate the effect of Lp(a) levels on arterial stiffness, endothelial function, and left atrial (LA) and left ventricular (LV) deformation over a 12-month follow-up period. Secondarily, the study will investigate: * a) The incidence of major adverse cardiovascular events (MACE), including cardiovascular death, acute myocardial infarction, and acute stroke. * b) The correlation between MACE incidence and parameters of arterial stiffness, endothelial function, and LA/LV deformation. * c) The levels of oxidative load markers. 3. Materials and Methods This observational study will include adults aged 18-75 years (regardless of gender) who visit the outpatient clinics of the 2nd University Cardiology Clinic at "Attikon" General Hospital. All participants will sign a consent form. A full medical history, clinical examination, and blood collection will be performed to determine levels of Total Cholesterol, LDL-C, HDL-C, triglycerides, and Lp(a) at each visit.. Participants will be divided into three groups: * Group A: Lp(a) ≥50 mg/dL with Total Cholesterol\<200 mg/dl * Group B : Lp(a) \<50 mg/dL. with Total Cholesterol\>200 mg/dl * Group C (Control): Lp(a) \<50 mg/dL. with Total Cholesterol\<200 mg/dl At each group n ≥ 100 participants are anticipated. Measurements at baseline, at 6 and at 12 months: * Arterial Stiffness: Determination of carotid-femoral pulse wave velocity (cf-PWV) using the Complior SP device and 24-hour pulse wave analysis with the Mobil-O-Graph device. * Endothelial Function: Measurement of the endothelial glycocalyx thickness of sublingual capillaries using a Sidestream Dark Field (SDF) camera (GlycoCheck). This is expressed through the perfused boundary region (PBR) index. * Cardiac Deformation: Use of two-dimensional strain (speckle tracking) to calculate the Global Longitudinal Strain (GLS) of the LV and LA strain. * Oxidative Load: Determination of malondialdehyde (MDA) and protein carbonyls (PCs) levels as markers of oxidative stress using spectrophotometric kits. Statistical Analysis: Comparisons regarding the changes in these markers over 6 and 12 months will be conducted between the three groups.

Atorvastatin Pretreatment in Cerebrovascular Events (APICES) After Flow Diverter Implantation

APICES trial is an investigator-initiated, multicenter, multicenter, randomized, double-blind, placebo-controlled clinical trial that plans to enroll 396 patients with a 1-year follow-up, including a neurovascular imaging examination \[digital subtraction angiography (DSA), CT angiography (CTA) or magnetic resonance angiography (MRA)\] at 6 months after index treatment. It was designed in compliance with the Declaration of Helsinki and the International Conference on Harmonization Good Clinical Practice guidelines. The study was approved by the Ethics Committee of Zhujiang Hospital of South Medical University (2024-KY-032-02) and registered at ClinicalTrials.gov (NCT06308952). The participants will be recruited from twelve advanced stroke centers in China.

Perioperative Outcomes After Neoadjuvant Therapy in Colorectal Cancer

This prospective study investigates the effects of neoadjuvant therapy on endothelial function, microvascular tissue density, and tissue fibrosis in patients with colorectal cancer and their association with perioperative complications. The primary objective is to assess differences in microvascular tissue density between patients who received neoadjuvant therapy and those who did not, biomarkers, and demographic factors between patients who received neoadjuvant therapy and those who underwent surgery as initial treatment, and to compare clinical outcomes. The study will include 34 patients treated with neoadjuvant therapy and 34 patients for whom surgery is the first-line treatment. Patients will be followed until discharge from the hospital, and complications after discharge will be monitored through medical records one month after surgery.

EndoPAT Device for Endothelial Dysfunction in ED

To assess endothelial dysfunction in young men (aged 30-50) with vasculogenic ED identified through penile Doppler ultrasound. To evaluate changes in endothelial function using EndoPAT before and 3-6 months after daily low-dose phosphodiesterase type 5 (PDE5) inhibitor therapy. To investigate endothelial function alterations in hypogonadal patients before and 3-6 months after initiating testosterone (T) therapy

Nailfold Capillaroscopy and Endothelial Biomarkers in Healthcare Workers Exposed to Chronic Low-Dose Ionizing Radiation

Chronic occupational exposure to low-dose ionizing radiation may lead to subclinical endothelial dysfunction and early microvascular alterations in healthcare workers. Nailfold capillaroscopy is a non-invasive method that allows direct visualization of microcirculatory changes. This observational study aims to evaluate microvascular alterations using nailfold capillaroscopy and to assess their association with serum endothelial and inflammatory biomarkers, including asymmetric dimethylarginine (ADMA), von Willebrand factor (vWF), high-sensitivity C-reactive protein (hs-CRP), and D-dimer levels. Healthcare workers with chronic low-dose radiation exposure will be compared with non-exposed controls. The study seeks to improve understanding of early vascular effects of occupational radiation exposure.

Inspiratory Muscle Strength Training for Lowering Blood Pressure and Improving Endothelial Function in Postmenopausal Women: Comparison With "Standard of Care" Aerobic Exercise

High blood pressure (BP) is the major modifiable risk factor for cardiovascular diseases (CVD) and related health conditions, particularly among postmenopausal (PM) women. In adults age ≥50 years this risk is primarily driven by above-normal systolic BP (SBP ≥120 mmHg), as diastolic BP plateaus, then decreases in older adulthood. Although SBP is lower in premenopausal women vs. age-matched men, SBP reaches, then surpasses men after age 60. As such, \>75% of PM women in the U.S. have above-normal SBP, which, in turn, is responsible for a 2-fold increase in risk of hypertension and corresponding increases in risk of CVD, chronic kidney disease and many other disorders. A key process linking high SBP to CVD and related conditions is vascular endothelial dysfunction, mediated by excessive reactive oxygen species (ROS)-induced oxidative stress and reductions in nitric oxide (NO) bioavailability. As the number of PM women is rapidly growing, further increases in SBP-related CV disorders are projected without effective intervention. * Aerobic exercise (AE) is a first-line, standard-of-care therapy for lowering BP. In PM women with baseline SBP ≥120 mmHg, AE reduces casual (resting) SBP by \~3 mmHg (back to baseline ≤4 weeks post-training), whereas 24-hour SBP is typically unchanged. However, only 25-30% of PM women meet guidelines for 150 min/week of moderate-intensity AE, citing the extensive time requirement, facility access and travel disruptions as major barriers. Another, far less recognized, limitation is that AE training consistently improves endothelial function in midlife/older men, but not in estrogen-deficient PM (PMe-) women, i.e., in \>95% of the 60+million PM women in the U.S. Thus, establishing new lifestyle therapies that induce and sustain reductions in SBP and increases in endothelial function in PMe- women with above-normal SBP is an important public health goal. * High-resistance inspiratory muscle strength training (IMST) is a time-efficient (5 minutes per session) lifestyle intervention consisting of 30 inspiratory maneuvers performed against a high resistance. Preliminary data suggest 6-weeks of IMST performed 6 days/week reduces SBP by 9 mmHg in adults with above-normal SBP (i.e., greater than 120 mmHg) at baseline. Importantly, this reduction in SBP is equal to or greater than the reduction in blood pressure typically achieved with time- and effort-intensive healthy lifestyle strategies like conventional aerobic exercise. In addition, IMST improved endothelial function in the PMe- women in a small pilot study. * To translate these promising preliminary results towards clinical practice, this randomized clinical trial is being conducted to directly compare the efficacy of a longer, clinically relevant treatment duration of IMST (3 months) against home-based, moderate-intensity (standard-of-care) AE in PMe-women. The primary outcome will be the change in casual SBP (IMST vs. AE). Changes in 24-hour SBP and endothelial function will serve as secondary outcomes. Effects on NO bioavailability, ROS/oxidative stress, and the role of "circulating factors" will provide insight into mechanisms of action. The sustained effects on SBP and endothelial function also will be assessed. * Accordingly, a randomized, blinded, sham-controlled, parallel group design clinical trial will be conducted to assess the efficacy of 3-months of IMST (75 percent maximal inspiratory pressure) vs. brisk walking (40-60% heart rate reserve; an established healthy lifestyle strategy) for lowering SBP and improving endothelial function in PMe- women age 50 years and older with above-normal SBP. It is hypothesized that IMST will lower SBP and improve endothelial function by decreasing oxidative stress and increasing nitric oxide bioavailability. It is also expect that adherence to the intervention will be excellent (over 80 percent of all training sessions completed at the appropriate intensity). * To test this hypothesis, 90 PMe- women age 50 years and older who have SBP \>/= 120 mmHg will be recruited. Participants will undergo baseline testing for casual (resting) SBP, 24-hour ambulatory SBP and endothelial function. Innovative mechanistic probes including pharmaco-dissection with vitamin C, analysis of biopsied endothelial cells, and high-throughput metabolomics, will be performed to assess oxidative stress and nitric oxide bioavailability at baseline. * After baseline testing, subjects will be randomized to perform either 3-months of high-resistance IMST or brisk walking. Subjects will train 6 days/week. Following 3 months of training, subjects will redo all the tests that were done during baseline testing to assess training-induced changes in SBP, physiological functions, and underlying mechanisms. Subjects will then cease training for 6 weeks before returning to the lab for follow-up testing to determine the persistent effects of IMST.

The DISCOVER INOCA Prospective Multi-center Registry

The overall objective of this multi-center registry is to identify specific phenotypes of INOCA with both an anatomic evaluation (coronary angiography and intravascular imaging) and physiologic assessment with the Abbott Coroventis Coroflow Cardiovascular System, and to determine long-term outcomes.

Role of Inflammation in Vascular Phenotype Associated With E-cigarette Use

The use of electronic nicotine delivery systems, or e-cigarettes - colloquially referred to as "vaping" - in the United States has increased exponentially since their introduction to the US market in 2007. Prevalence of ever and current e-cigarette use is highest among teenagers and young adults with 16-28% of this population having reported vaping. While the majority of e-cigarette users are current tobacco smokers, 32.5% of current e-cigarette users are never- or former-smokers, representing a growing population of young adults who exclusively vape. While e-cigarettes have been marketed as a safer alternative to tobacco cigarettes, clinical studies examining these claims are limited. Cardiovascular disease (CVD) is the primary cause of premature death among tobacco cigarette smokers and reductions in vascular endothelial function, a significant predictor of future CVD, are detectible in otherwise healthy young adults who smoke. Despite the explosion in e-cigarette use among young adults, the health effects - especially the effects on mechanisms of vascular function - of these devices remain relatively unexplored. The purpose of this study is to directly asses the mechanistic role of inflammation in this dysfunction.

The Iowa ACEs and Sleep Cohort and Manipulating Sleep in Young Adults With ACEs Studies

The overall purpose of this study is to understand the role of disrupted sleep in the association of exposure to early life adversity (adverse childhood experiences (ACEs)) with vascular endothelial (dys)function. In Aim 1 (The Iowa ACEs and Sleep Cohort Study), the investigators will utilize a cross-sectional cohort design with a state-of-the-art translational approach. Participants will be recruited to objectively characterize the degree to which lower sleep quality and quantity contribute to ACEs-related endothelial dysfunction, inflammation, and oxidative stress in young adults using: 1. rigorous at home sleep monitoring using 7-nights of wrist actigraphy and 2 nights of home-based polysomnography to objectively measure sleep quality (sleep efficiency, wakefulness after sleep onset and sleep depth), and total sleep duration, 2. in vivo assessment of endothelial function via flow-mediated dilation testing, and 3. in vitro determination of endothelial cell inflammation and oxidative stress from biopsied endothelial cells. This study to achieve this Aim. In Aim 2, approximately 70 eligible participants from Aim 1 (The Iowa ACEs and Sleep Cohort Study) will then be randomized to either a 6-week behavioral sleep intervention (cognitive behavioral therapy for insomnia) or a wait-list control to determine the mechanistic contribution of sleep disruption to vascular dysfunction in young adults with moderate-to-high exposure to adverse childhood experiences (ACEs). Following the intervention, participants will again complete: 1. rigorous at home sleep monitoring using 7-nights of wrist actigraphy and 2 nights of home-based polysomnography to objectively measure sleep quality (sleep efficiency, wakefulness after sleep onset and sleep depth), and total sleep duration, 2. in vivo assessment of endothelial function via flow-mediated dilation testing, and 3. in vitro determination of endothelial cell inflammation and oxidative stress from biopsied endothelial cells.

Microvascular Dysfunction in Obesity

Impaired endothelial function is observed in disease states related to obesity, such as atherosclerosis, coronary artery disease, and diabetes. Reactive oxygen species (ROS) production and resultant oxidative stress contribute to the development of these obesity-related diseases. The enzyme NADPH-oxidase is a major source of oxidative stress within the vasculature, and has been linked with the Metabolic Syndrome. In the investigator's previously funded studies, the investigators demonstrated for the first time that: 1) in vivo ROS were elevated in skeletal muscle of obese as compared to lean or overweight human subjects, 2) perfusion of the NADPH-oxidase inhibitor apocynin locally into muscle normalized ROS levels and reversed local microvascular endothelial dysfunction in the obese individuals, and 3) aerobic exercise training was effective at attenuating in vivo hydrogen peroxide production and reversing microvascular endothelial dysfunction in the obese individuals. The investigators will investigate in this R15 renewal application the mechanism of exercise training-induced alterations in ROS production and action on endothelial dysfunction in obesity using our newly developed microdialysis methodology of monitoring ROS production, in combination with analysis of muscle biopsy samples obtained before and after our previously tested 8-week intervention of aerobic interval exercise training. The objectives of this study are to determine the impact of in vivo NADPH oxidase activity on endothelial function in obese individuals, and to determine the mechanism of training-induced improvements in endothelial function. The investigator's unique microdialysis methodology will allow monitoring of microvascular/endothelial function and ROS generation, as well as the administration of pharmacological agents directly into muscle. The central hypothesis is that it is upregulation of both mitochondrial ROS and NADPH oxidase-derived ROS that results in endothelial dysfunction in obesity, and that exercise training down-regulates mitochondrial-derived ROS, and NADPH oxidase 4, thereby improving endothelial function. The aims of this proposal are to: 1) determine the contributions of mitochondrial ROS and specific NADPH oxidase isoforms to the NADPH oxidase dependent endothelial dysfunction in skeletal muscle of obese individuals; 2) determine the mechanism of ROS reduction and improved endothelial function resulting from an 8-week aerobic interval training program.

Role of ET-1, Physical Activity, and Sedentary Behavior in Microvascular Dysfunction Following GDM

Women with a history of gestational diabetes mellitus (GDM) are at a 2-fold greater risk for the development of overt cardiovascular disease (CVD) following the effected pregnancy. While subsequent development of type II diabetes elevates this risk, prior GDM is an independent risk factor for CVD morbidity, particularly, within the first decade postpartum. GDM is associated with impaired endothelial function during pregnancy and decrements in macro- and microvascular function persist postpartum, despite the remission of insulin resistance following delivery. Collectively, while the association between GDM and elevated lifetime CVD risk is clear, and available evidence demonstrates a link between GDM and vascular dysfunction in the decade following pregnancy, the mechanisms mediating this persistent dysfunction remain unexamined. The purpose of this investigation is to examine the role of endothelin-1, a potent vasoconstrictor, in aberrant microvascular function in otherwise healthy women with a history of GDM and to identify whether this mechanism is influenced by physical activity and sedentary behavior.

Study to Assess Safety and Tolerability of Multiple Doses of EO2002

The goal of this clinical study is to assess the safety of multiple intracameral injections of EO2002 with and without topical Ripasudil.

Testosterone Deficiency and Endothelial Dysfunction After Spinal Cord Injury

Heart attacks and strokes are among the most common causes of premature death in individuals living with spinal cord injury (SCI) and appear to occur earlier in life. The factors that lead to the heighten and accelerated risk of heart attacks and strokes in adults living with SCI remain poorly understood. The investigators aim to uncover why this happens and find ways to prevent it. Our research focuses on how important cells which line blood vessels, called endothelial cells, function after SCI. The investigators test endothelial function in live conscious people with SCI. The investigators also study signaling molecules endothelial cells release called endothelial cell derived microvesicles (EMVs), which the investigators can measure in blood to tell us the health of endothelial cells. By using these rigorous tests of vascular function, the investigators have determined that endothelial cells appear dysfunctional after SCI. The investigators also know that many men with SCI have low testosterone levels. Our team has studied testosterone's effects on endothelial dysfunction and believe low testosterone may be contributing to endothelial dysfunction after SCI. By understanding these mechanisms, the investigators hope to improve the lives of those living with SCI and reduce their risk for heart attacks and strokes. The investigators propose to study the influence of testosterone on endothelial function by using state-of-the-art clinical and laboratory experiments to assess endothelial function in men with SCI with low and normal testosterone levels.

Wild Blueberries and Cardiovascular Health in Middle-aged/Older Men and Postmenopausal Women

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide. Aging is the primary risk factor for CVD, in large part due to adverse modifications to the arteries. These modifications include vascular endothelial dysfunction and arterial stiffness. Vascular endothelial dysfunction is an initiating step in atherosclerosis, and is primarily caused by reduced nitric oxide (NO) bioavailability secondary to excessive superoxide-driven oxidative stress and inflammation. Endothelial dysfunction leads to arterial stiffness and the development of hypertension (HTN) which further increases CVD. Greater than 2/3 of the US population has elevated blood pressure or stage 1-HTN. As such, interventions that improve vascular endothelial dysfunction by increasing NO bioavailability and mitigating excessive oxidative stress and inflammation are needed. Blueberries are rich in bioactive compounds including flavonoids, phenolic acids, and pterostilbene. These compounds and their metabolites have been shown to attenuate oxidative stress and inflammation. The primary goal of this study is to assess the efficacy of blueberries to improve reduce blood pressure and improve vascular endothelial dysfunction and arterial stiffness in middle-aged/older men with elevated blood pressure or stage 1-HTN.

Role of Endothelial Dysfunction on Exercise Pressor Reflex in Type 2 Diabetes

Exaggerated blood pressure responses to exercise in individuals with Type 2 Diabetes significantly increase the risk of heart attack, stroke, and cardiovascular death, while also limiting exercise capacity and therapeutic benefits of physical activity. This research will determine whether impaired blood vessel function and excessive cellular damage from oxygen-containing molecules cause these dangerous blood pressure responses during exercise. The findings will establish whether targeting cellular antioxidant systems represents a new therapeutic approach to improve exercise tolerance and reduce cardiovascular risk in t Americans living with diabetes.

Endothelial Dysfunction After SCI

This study plans to learn how endothelial cells, single cell lining of blood vessels may be dysfunctional after a spinal cord injury. Endothelial dysfunction will be measured by the capacity of blood vessels to vasodilate (increase in size) and alter blood flow is lower in adults with a spinal cord injury in comparison to adults without a spinal cord injury. The mechanisms which may alter this function may be critical in reducing the risk of heart attacks and strokes in people with spinal cord injuries.

Fisetin to Improve Vascular Function in Older Adults

This is a pilot clinical trial to test the efficacy of intermittent treatment with the flavonoid compound fisetin for improving vascular endothelial function and reducing aortic stiffness in older adults. This trial will also determine the potential mechanisms by which fisetin may improve vascular function, including by decreasing mitochondrial oxidative stress, cellular senescence and senescence-associated secretory phenotype (SASP) factors in circulation. Lastly, safety, tolerability and adherence of fisetin treatment will be assessed.