42 Clinical Trials for Various Conditions
The investigators will test the hypothesis that markers of vascular endothelial dysfunction will be exaggerated acutely with an extreme high sodium diet compared to an extreme low-sodium diet. The investigators will compare patients with postural orthostatic tachycardia (POTS) to healthy control subjects.
Improvement in cardiovascular mortality is related to changes in pathologic autoantibodies and in the number of circulating functional replicative competent endothelial progenitor cells (EPC's) after bariatric surgery.
Prolonged periods of reduced activity are associated with decreased vascular function and muscle atrophy. Physical inactivity due to a sedentary lifestyle or acute hospitalization is also associated with impaired recovery, hospital readmission, and increased mortality. Older adults are a particularly vulnerable population as functional (vascular and skeletal muscle mitochondrial dysfunction) and structural deficits (loss in muscle mass leading to a reduction in strength) are a consequence of the aging process. The combination of inactivity and aging poses an added health threat to these individuals by accelerating the negative impact on vascular and skeletal muscle function and dysfunction. The underlying factors leading to vascular and skeletal muscle dysfunction are unknown, but have been linked to increases in oxidative stress. Additionally, there is a lack of understanding of how vascular function is impacted by inactivity in humans and how these changes are related to skeletal muscle function. It is the goal of this study to investigate the mechanisms that contribute to disuse muscle atrophy and vascular dysfunction in order to diminish their negative impact, and preserve vascular and skeletal muscle function.
Prolonged periods of reduced activity are associated with decreased vascular function and muscle atrophy. Physical inactivity due to acute hospitalization is also associated with impaired recovery, hospital readmission, and increased mortality. Older adults are a particularly vulnerable population as functional (vascular and skeletal muscle mitochondrial dysfunction) and structural deficits (loss in muscle mass leading to a reduction in strength) are a consequence of the aging process. The combination of inactivity and aging poses an added health threat to these individuals by accelerating the negative impact on vascular and skeletal muscle function and dysfunction. The underlying factors leading to vascular and skeletal muscle dysfunction are unknown, but have been linked to increases in oxidative stress. Additionally, there is a lack of understanding of how vascular function is impacted by inactivity in humans and how these changes are related to skeletal muscle function. It is our goal to investigate the mechanisms that contribute to disuse muscle atrophy and vascular dysfunction in order to diminish their negative impact, and preserve vascular and skeletal muscle function across all the lifespan.
This clinical research study will investigate the dose of inspiratory muscle strength training needed to maintain cardiovascular adaptations induced by a six-week loading dose.
A randomized crossover trial to determine the effects of sodium loading and aldosterone infusion on endothelial function in normal subjects.
To determine the effects of chronic sertraline treatment on brachial artery flow-mediated dilation in patients with chronic heart failure and depression
The purpose of this study is to examine the effect of acute ingestion of a concentrated beetroot juice supplement on vascular function and exercise capacity in patients with moderate to severe chronic kidney disease
The purpose of this study is to determine the effects of dietary salt restriction on central hemodynamics and vascular function in men and women with salt resistant blood pressure.
The investigators aim to conduct a 3-period randomized controlled crossover study to investigate the postprandial effects of a high fat meal with spice on endothelial function, lipids/lipoproteins, immune function and plasma markers of antioxidants and oxidative stress. Metabolomic profiling will also be conducted. In random order, participants will consume either a high fat meal (1000kcal, 45g fat) or a high fat meal containing 2g of spice or a high fat meal containing 6g of spice. Between each treatment there will be a washout period of at least 3 days. It is hypothesized that consumption of a high fat meal with spice will attenuate postprandial endothelial impairment and triglyceride levels in a dose response manner compared with a high fat meal.
The purpose of this study is to examine the effect of mitochondria derived oxidative stress on vascular function in patients with moderate to severe Chronic Kidney Disease.
The purpose of this study is to investigate the effects of 12 weeks of aerobic exercise training on blood vessel function in Stages 1-4 Chronic Kidney Disease.
The study is being performed to determine whether sitagliptin, a dipeptidyl peptidase-4 inhibitor, both acutely and chronically improves blood vessel function. Patients with type 2 diabetes who are on metformin will be enrolled in this study for up to 22 weeks in this double blinded cross over study where they will receive a sitagliptin pill once a day for 8 weeks and during a separate 8 weeks receive a matching placebo pill. The treatment periods are divided by a 4 week period. Blood vessel function will be measured by ultrasound before and after a single dose of sitagliptin and placebo, as well as after 8 weeks of treatment with each. Blood will also be taken to measure blood markers of inflammation at each time the ultrasounds are performed.
Risk of cardiovascular diseases (CVD) is significantly elevated in patients with chronic kidney disease (CKD); however, this increased risk is only partially explained by traditional cardiovascular risk factors. Patients with CKD exhibit chronic inflammation, a key mechanism contributing to vascular dysfunction (i.e., large elastic artery stiffening and endothelial dysfunction). Inhibiting inflammation improves vascular dysfunction in other populations characterized by chronic inflammation. However, it is currently unknown if reducing inflammation with an interleukin-1 (IL-1) blocker enhances vascular function in CKD patients. Aim 1 will assess the efficacy of IL-1 blocking with rilonacept for treating vascular dysfunction in patients with stage III or IV CKD (estimated glomerular filtration rate 15-60 mL/min/1.73 m2). Aim 2 will determine if blocking IL-1 with rilonacept also reduces inflammation and oxidative stress. These studies could shift clinical practice guidelines by establishing a novel therapy for reducing CVD risk in CKD patients not requiring chronic hemodialysis.
The purpose of this study is to determine whether storage time affects how human body responds to autologous blood transfusion. An autologous blood transfusion is when a person donates blood and then receives that same blood back in the transfusion. We also want to find out if in this situation inhaled nitric oxide can help to prevent the potential reduction of vasodilation capacity. Vasodilation capacity is the ability of the blood vessel to widen when needed.
The objective of this study is to assess effects of the storage of PRBC on endothelial function, inflammation and platelet activation in healthy volunteers
The American Heart Association (AHA) and American College of Sports Medicine (ASCM) recommend older adults (50≤ age ≤ 80) perform at least 30 minutes of moderate-intensity aerobic exercise on most days ( ≥5 days) of the week. This suggestion arises, in part, from data supporting that regular physical activity reduces the risk of adverse cardiovascular events A portion of these benefits may be from reductions in the incidence and severity of cardiovascular risk factors, including diabetes mellitus, obesity, and hypertension. While this recommendation for physical activity has been in existence for almost 15 years, the rates of obesity in the United States continue to rise and prevalence of sedentarism remains at best unchanged. Researchers have been engaged in investigating novel interventions to designed increase physical activity to reach the recommended activity targets. One promising intervention involves use of inexpensive, easy to use pedometers that allow individuals to objectively track the number of steps taken during a set period of time. Recent data suggest that an average of 10,000 steps/day as measured by a pedometer accurately estimates the activity levels recommended by the AHA, ASCM, and US government public health guidelines. While the benefits of habitual exercise are well-documented, there are no data that demonstrate current recommendations for moderate physical activity in older adults by the ASCM, AHA, and US public health guidelines reduce the risk of adverse cardiovascular events. Interestingly, prior work indicates that pedometer-centered interventions can increase physical activity, suggesting that this type of intervention could potentially lead to cardiovascular benefits. Using validated surrogate markers of cardiovascular risk including brachial artery endothelial function, tonometric measurements of vascular stiffness, and measurements derived from transthoracic echocardiography, we will determine whether increasing the physical activity of sedentary adults to an average of 10,000 steps or more/day translates into improvements in cardiovascular health. This will be determined in the context of a randomized control trial employing a control group, a study group that uses a pedometer alone, and an intervention that couples a pedometer with internet-based motivational messaging software demonstrated in our preliminary data to encourage older adults to reach and exceed the 10,000 steps/day goal.
This is a substudy of ACTG A5142. The purpose of this substudy is to evaluate blood vessel function in HIV-infected patients taking anti-HIV drugs.
Nitric oxide (NO) is a soluble gas, continuously synthesized by the endothelium, that contributes importantly to vasodilator tone of the coronary and systemic circulations by activating guanylyl cyclase in vascular smooth muscle, causing relaxation. Although regional synthesis of NO by the endothelium contributes to local vasodilator tone, Stamler and co-workers have proposed that regional vascular tone may also be regulated by NO transported from the lungs by hemoglobin as a consequence of enhanced binding of NO to reactive thiols of oxygenated hemoglobin. This study is designed to determine the contribution of hemoglobin-transported NO to forearm microvascular dilator tone in healthy subjects at rest and during regional hypoxia associated with forearm exercise stress, with measurements made before and after regional blockade of endothelial NO synthesis. Findings in this study may be relevant to understanding the physiological contribution and therapeutic potential of hemoglobin-transported NO in the regulation of vasodilator tone in diseases and conditions associated with regional endothelial dysfunction and reduced endothelial NO bioactivity (e.g., hypertension, diabetes mellitus, hypercholesterolemia, cigarette smoking, and estrogen deficiency).
The purpose of this study is to determine whether reducing inflammation in blood vessels with an aspirin-like drug called salsalate will improve blood vessel function.
The goal of this clinical trial is to better understand how day-to-day stress affects cardiovascular health and brain function in middle-aged adults. The main question is aims to answer is whether the link between daily stress and vascular dysfunction is a potential mechanism of increased risk for future cognitive decline. Participants will complete two 15-day "testing cycles" separated by \~6 months. During each cycle, participants will complete two daily assessments of stress and brain health using an online survey tool for 14-consecutive days. On the last day of each cycle, vascular function will be assessed during a laboratory visit.
The goal of this clinical trial is to determine the effect of elevated plasma ceramides on peripheral vascular function. Subjects will consume a high fat meal consisting of long chain fatty acids (to increase plasma ceramides) or medium chain fatty acids (control). Subjects' vascular function will be assessed with laser Doppler flowmetry to measure their artery function and with the CytoCam device to assess their peripheral microvascular endothelial function.
The Vendys II, an FDA-approved device, uses finger digital thermal monitoring (DTM) after a period of blood flow restriction to evaluate vascular health. This study will evaluate the feasibility of using this device to measure the Vascular Reactivity Index (VRI) in children and adolescents/young adults (AYA) undergoing hematopoietic cell transplantation (HCT).
Postmenopausal women are at an increased risk of developing cardiovascular disease (CVD) largely due to accelerated aging-related modifications to vascular health following menopause. The vascular endothelium is responsible for producing chemicals that are essential for proper vasodilation and blood flow and therefore is involved in maintaining normal blood pressure. A major modification that occurs during aging and is accelerated during menopause is termed vascular endothelial dysfunction which is characterized by impaired endothelium-dependent dilation. This can lead to increased blood pressure, atherosclerosis, and increased risk of CVD and death. Nitric oxide (NO) is a chemical produced by the endothelium and is essential for normal endothelial function and cardiovascular health. Vascular endothelial dysfunction is primarily caused by reduced NO bioavailability secondary to excessive oxidative stress. Approximately 3/4 of postmenopausal women have elevated blood pressure or hypertension which further worsens endothelial function and increases CVD risk through increased oxidative stress and inflammation. Blueberries are rich in phytochemicals including anthocyanins, phenolic acids, and pterostilbene. These phytochemicals and their metabolites are known to attenuate oxidative stress and inflammation. The overall goal of the current study is to assess the efficacy of blueberries to improve vascular endothelial dysfunction in this high-risk population and to gain insight into underlying mechanisms. 58 postmenopausal women with elevated blood pressure and stage 1-HTN will be asked to consume 22 grams freeze-dried blueberry powder or placebo powder per day for 12 weeks. Vascular endothelial function will be assessed at baseline and 12 weeks. Measurements indicative of vascular nitric oxide production, oxidative stress, inflammation, cardiometabolic health, cognitive function, and blueberry phytochemical metabolism will be measured at baseline and 12 weeks. Blood pressure will be assessed at baseline and 4, 8, and 12 weeks.
The purpose of this study is to compare the cardiovascular profiles of efavirenz and rilpivirine, which are two drugs used to treat HIV infection.
The study hypothesis is that 6 weeks of repetitive handgrip exercise will improve endothelial function and venous compliance in pre-dialysis patients with an estimated glomerular filtration rate of less than or equal to 20 ml/min. If proven correct then arm exercise might be useful to improve the success rate for a surgically created arteriovenous fistula in the forearm to become usable as a vascular access for hemodialysis.
This study will test the hypothesis that reducing the release of free fatty acids (FFA) from fat cells will restore insulin-mediated, endothelium-dependent vasodilation in people with the metabolic syndrome.
This study will test the hypothesis that reduction in release of free fatty acids from adipocytes will restore insulin-mediated endothelium-dependent vasodilation and skeletal muscle glucose metabolism in subject with type 2 diabetes.
Nitric oxide gas is important in regulating blood vessel dilation, and consequently, blood flow. This gas is continuously produced by endothelial cells, which line the blood vessels. This study will examine whether nitrite, a molecule that normally circulates in the blood stream, can also dilate blood vessels. The results of this study may be valuable in developing treatments for people with conditions associated with impaired endothelial production of nitric oxide, including high blood pressure, high blood cholesterol, diabetes, estrogen deficiency, and others. Healthy, non-smoking normal volunteers 21 years of age or older may be eligible for this study. People who lack the enzyme G6PD or cytochrome B5 in their red blood cells may not participate. Absence of these enzymes can lead to episodes of sudden shortness of breath and cyanosis (blueness of the skin due to lack of sufficient oxygen). Participants will undergo the procedures described in study Parts A and B, as follows: * Part A - After numbing the skin, small tubes are placed in the artery and vein at the inside of the elbow of the dominant arm (right- or left-handed) and a small tube is placed in a vein of the other arm. The tubes are used for infusing saline (salt water) and for drawing blood samples. A pressure cuff is placed around the upper part of the dominant arm, and a rubber band device called a strain gauge is also placed around the arm to measure blood flow. When the cuff is inflated, blood flows into the arm, stretching the strain gauge at a rate proportional to the flow. Grip-strength of the dominant arm is measured with a dynamometer to determine maximum grip-strength. Then, several measurements of blood flow, nitrite, hemoglobin, and handgrip are made before and after administration of L-NMMA, a drug that blocks endothelial production of nitric oxide. * Part B - Part A testing is repeated, except that sodium nitrite dissolved in a saline solution is infused into the artery of the forearm for a few minutes before and during the hand-grip exercises. In addition, blood samples are drawn before and after each handgrip exercise to measure methemoglobin, a substance that, at excessive levels, can cause adverse side effects.
This study will examine the use of magnetic resonance imaging (MRI) in detecting blood vessel inflammation. The results of this study may later be applied to diagnosing inflammation of arteries in patients with atherosclerosis, predicting disease progression in these patients, and guiding therapy. Patients with peripheral artery disease (for example, blockage of a leg artery) undergoing balloon angioplasty at Suburban Hospital in Bethesda, Maryland, may be eligible to participate in this study. Because this procedure, which opens blocked arteries, can cause inflammation in the vessel wall, it affords an opportunity for studying MRI detection of such inflammation. Study candidates will be screened with a medical history and physical examination. Participants will have a MRI scan and blood drawn at Suburban Hospital before the angioplasty and again either 1 to 3 days or 2 weeks after the procedure. Before the MRI scan is begun, a catheter (a thin plastic tube) is inserted in an arm vein and 90 milliliters (about 3 ounces) of blood is drawn. The patient then lies on a table that slides into the MRI scanner-a large donut-shaped machine with a magnetic field. A flexible, padded sensor called an MRI coil is placed over the area to be imaged; this device is used to improve the quality of the pictures. During the scan a contrast material called gadolinium is injected through the catheter. Gadolinium brightens the image of the blood vessels. The procedure lasts up to 2 hours.