Endothelial Dysfunction Clinical Trials

Above-normal systolic blood pressure (SBP), defined as SBP >/= 120 mmHg, is the major modifiable risk factor for cardiovascular disease, stroke, cognitive decline/dementia, and other chronic health problems. Despite the availability of treatments to lower SBP, over 75 percent of adults with above-normal SBP fail to control BP, which has led to a nearly 50 percent increase in the number of deaths attributable to BP over the past decade. Therefore, above-normal SBP is a major public health burden. Greater than 65 percent of adults 50 years of age and older have above-normal SBP. The number of adults age 50 years and older is rapidly increasing, predicting a continued increase in above-normal SBP driven morbidity and mortality in the absence of effective treatment strategies. This makes developing novel SBP-lowering therapies an urgent biomedical research priority. Increasing SBP is closely linked to vascular dysfunction, observable as impaired endothelial function, increased large-elastic artery stiffness, and impaired cerebrovascular function. Declines in these functions play a large role in the increased risk of chronic disease associated with above-normal SBP. The primary mechanism responsible for SBP-induced vascular dysfunction is thought to be oxidative stress-associated inhibition of nitric oxide bioavailability. Therefore, to have the largest biomedical impact, new SBP-lowering therapies should also improve vascular function by decreasing oxidative stress. Healthy lifestyle practices, such as conventional aerobic exercise, maintaining a healthy diet, or reducing sodium intake, are all first-line strategies to lower SBP. Importantly, these lifestyle practices also improve vascular function, in large part by reducing oxidative stress. However, adherence to healthy lifestyle practices is poor, with adherence to guidelines generally between 20 to 40 percent in adult Americans. The greatest reported barrier to meeting healthy lifestyle guidelines is lack of time. Therefore, time-efficient interventions have great promise for promoting adherence, reducing SBP, and improving other physiological functions. 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. However, these results need to be confirmed in an appropriately powered clinical trial with a longer, guideline-based treatment duration. Furthermore, the influence of IMST on functions impaired by above-normal SBP (endothelial, cerebrovascular, cognitive) needs to be determined, as do the mechanisms through which IMST exerts beneficial effects. Accordingly, we will conduct a randomized, blinded, sham-controlled, parallel group design clinical trial 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, cerebrovascular, and cognitive function in adults age 50 years and older with above-normal SBP. I hypothesize IMST will lower SBP and improve endothelial function by decreasing oxidative stress and increasing nitric oxide bioavailability. I also hypothesize IMST will improve cerebrovascular and cognitive function, and that these improvements will be related to reductions in SBP and improvements in endothelial function. I also expect adherence to the intervention to be excellent (over 80 percent of all training sessions completed at the appropriate intensity). To test my hypothesis, I will recruit 102 adults age 50 years and older who have SBP >/= 120 mmHg. Subjects will undergo baseline testing for casual (resting) SBP, 24-hour ambulatory SBP, endothelial function, arterial stiffness, cognitive function, and cerebrovascular 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 with one training session supervised in the laboratory and the other 5 performed unsupervised at home. 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. Read Less

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). Read Less

This research study seeks to determine the effects of an enzyme in the human body called NADPH oxidase (NOX) on blood flow. In addition, the study will investigate the benefits of creatine monohydrate, a common sports performance supplement, on blood food and vessel function. Participants will undergo two study arms, one in which they consume a high carbohydrate meal pre- and post-creatine monohydrate supplementation and one in which they will consume a high carbohydrate meal pre- and post-placebo supplementation. Blood flow and endothelial function will be assessed before and for 4 hours following the consumption of a high-carbohydrate meal pre and post-supplementation (creatine monohydrate and placebo). Read Less

Diabetic kidney disease and cardiovascular disease remain the leading causes of morbidity and mortality in people with type 1 diabetes and are exacerbated with longer duration of diabetes and time outside goal glycemic range. Yet, type 1 diabetes is a complex disease with pathophysiology that extends beyond beta-cell injury and insulin deficiency to include insulin resistance and renal vascular resistance, factors that accelerate cardiovascular disease risk. We have shown that metformin improved peripheral insulin sensitivity and vascular stiffness in youth with type 1 diabetes on multiple daily insulin injections or standard insulin pumps. However, metformin's effect on kidney and endothelial outcomes, and the effects of type 1 diabetes technologies, with or without metformin, on any cardiovascular or kidney outcome, remains unknown. Automated insulin delivery systems combine an insulin pump, continuous glucose monitor, and control algorithm to modulate background insulin delivery and decrease peripheral insulin exposure while improving time in target range and reducing hypoglycemia. We hypothesize that automated insulin delivery systems, particularly when combined with metformin, may modulate renal vascular resistance and insulin sensitivity, thereby impacting cardiometabolic function. MANATEE-T1D is a randomized, double-blind, placebo-controlled trial of 4 months of metformin 2,000 mg daily in 40 youth aged 12-21 years with type 1 diabetes on automated insulin delivery systems vs. 20 control youth with type 1 diabetes on multiple daily injections plus a continuous glucose monitor which will assess for changes in calculated renal vascular resistance and gold standard measures of whole-body and adipose insulin sensitivity, arterial stiffness, and endothelial function. Read Less

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. Read Less

The goal of this clinical trial is to see how small blood vessels respond to the stress of high intensity exercise, and if a safe and simple intervention called ischemic conditioning can protect blood vessels from the stress of exercise. Participants will come in for 3 study visits and get home-based ischemic conditioning. At Study Visit 1, participants will be assessed for their frailty and physical function. Afterwards, they will perform an exercise test. At Study Visit 2, patients will undergo 2 microvascular assessments, perform a high-intensity exercise, then undergo the same 2 microvascular assessments again. Participants will be given a handheld sphygmomanometer and a blood pressure cuff to take home. Depending on which group the participants get randomized into, participants will place the blood pressure cuff around their non-dominant upper arm and inflate to either a low or high pressure for 2 weeks at home. Participants will repeat the same steps in Study Visit 2 for Study Visit 3. In addition, participants will also be assessed for their frailty and physical function. Read Less

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. Read Less

The goal of this mechanistic clinical trial is to learn about the effects of medications called soluble guanylyl cyclase stimulators on vascular function and markers of kidney and brain injury in patients having heart surgery. The main questions it aims to answer are: Does soluble guanylyl cyclase stimulation improve blood vessel function compared to placebo? Does soluble guanylyl cyclase stimulation decrease markers of kidney injury and brain injury compared to placebo? Participants will be randomized to a soluble guanylyl cyclase stimulator called vericiguat or placebo, and researchers will compare vascular function and markers of brain and kidney injury to see if vericiguat improves vascular function and reduces markers of injury. This will provide important information to determine the underlying reasons that patients have some kidney and brain function problems after having heart surgery. Read Less

In a young and 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 promote 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 even coronary artery disease later on in life in these patients. Therefore, the ability to somehow 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. COMP-4 is a safe, clinically available, well tolerated oral supplement that has been shown in the lab to increase NO production in a number of differing tissues including human vascular endothelial cells. In this proposed human study, the investigators plan on recruiting healthy, young participants willing to take COMP-4 for a 14 day period in whom the investigators will measure in a non-invasive way - by the use of ultrasound - the effect of COMP-4 on its ability to improve blood flow in one of the major blood vessels of the upper arm. In addition, the investigators will also determine whether COMP-4 will be capable of lowering in the blood the levels of two of the most studied inflammatory markers associated with endothelial dysfunction, IL-8 and PAI-1. Read Less

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. Read Less

The purpose of this study is to determine whether NightWare therapeutic intervention improves biomarkers of vascular aging and autonomic function in adults with nightmares related to PTSD. Read Less

The purpose of this study is to explore the influence of biological sex on sodium-induced blood pressure and vascular function responses to variations in sodium intake in African American/Black adults. Read Less