The goal of this clinical trial is to investigate whether metformin improves vascular function in individuals with prediabetes. The main questions it aims to answer are:
1. Does metformin improve large conduit artery endothelial function in individuals with prediabetes?
2. Does metformin improve microvascular endothelial function in individuals with prediabetes?
Researchers will compare metformin to a placebo to see if metformin improves vascular function in prediabetes.
The trial duration is 12 weeks. Participants will take metformin or a placebo once a day for 2 weeks. After 2 weeks, participants will take metformin or a placebo twice a day for the remaining 10 weeks. There will be a screening visit, two baseline visits, a 4-week safety visit, and two 12-week end-of-study visits. Adherence will be calculated from pill count and adverse events will be quantified via a questionnaire.
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.
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.
Heart disease is the leading cause of death globally, accounting for 16% of the world's total deaths. The number of cases is expected to increase as our population ages. Heart disease also results in large economic burden. It costs the United States about $219 billion per year. Some patients have symptoms that aren't helped by drugs or other medical treatments. These patients will need a surgery that is called cardiac artery bypass graft (CABG) surgery. CABG helps to improve chest pain which is one of the most common complaints of heart disease, and has life-prolonging potential. A limitation of CABG is that it results in increased inflammation. These patients also report high levels of anxiety and depression. Depression and anxiety in the several days surrounding surgery are related to several important things. These include worse health outcomes, worse quality of life, increased risk of death, and increased health care cost. Acceptance and Commitment Therapy (ACT) is a kind of therapy. ACT is adaptable, easy to access, and effective in brief formats. ACT has been gaining evidence for its use in many patient samples. Few studies have used ACT with heart disease patients. No known studies currently exist that have used ACT within the few days surrounding CABG surgery. To address this need, the investigators will conduct a two-arm feasibility randomized control trial (RCT). Patients will be randomized to one of two groups. The first group will complete a brief, 2-session telehealth ACT intervention. The second group will be a control group. The control will consist of treatment as usual. The investigators will evaluate the feasibility of this brief ACT intervention delivered in the peri-operative period. The investigators will also examine preliminary efficacy of the ACT intervention. The investigators will examine anxiety, depression, psychological inflexibility, well-being, and cardiovascular health-related quality of life. The investigators will also examine the intervention's impact on inflammation by measuring two inflammatory markers. The results from this study will also lay the groundwork for larger or multiple site RCT studies.
The study will enroll 200 women newly diagnosed with peripartum cardiomyopathy within 5 months postpartum in a randomized placebo controlled trial of bromocriptine therapy to evaluate its impact on myocardial recovery and clinical outcomes. Given that bromocriptine prevents breastfeeding, an additional 50 women with peripartum cardiomyopathy excluded from the trial due to a desire to continue breastfeeding but meeting all other entry criteria will be followed in an observational cohort.
Otherwise healthy women who develop preeclampsia during pregnancy are more likely to develop and die of cardiovascular disease later in life. The reason why this occurs is unclear but may be related to impaired endothelial function and dysregulation of the angiotensin system that occurs during preeclampsia and persists postpartum, despite the remission of clinical symptoms. The purpose of this investigation is to determine the mechanisms contributing to this lasting blood vessel damage caused by reduced endothelial function in women who have had preeclampsia compared to women who had a healthy pregnancy. Identification of these mechanisms and treatment strategies may lead to better clinical management of cardiovascular disease risk in these women.
The purpose of this study is to examine differences in the microvascular balance of angiotensin II receptors women who have had preeclampsia. This will help the investigators better understand the mechanisms of dysregulated angiotensin II receptors in formerly preeclamptic women, and how activation or inhibition of these receptors may restore microvascular function.
In this study, the investigators use the blood vessels in the skin as a representative vascular bed for examining mechanisms of microvascular dysfunction in humans. Using a minimally invasive technique (intradermal microdialysis for the local delivery of pharmaceutical agents) the investigators examine the blood vessels in a dime-sized area of the skin.
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.
In this study, we use the blood vessels in the skin as a representative vascular bed for examining mechanisms of microvascular dysfunction in humans. Using a minimally invasive technique (intradermal microdialysis for the local delivery of pharmaceutical agents) we examine the blood vessels in a dime-sized area of the skin in otherwise healthy young (18-24yrs) chronic e-cigarette users. Local heating of the skin at the microdialysis sites is used to explore differences in mechanisms governing microvascular control. As a compliment to these measurements, we also draw blood from the subjects to measure circulating factors that may contribute to cardiovascular health and examine markers of inflammatory activation. We will also collect urine from female participants to measure estradiol.
A clinical trial of exercise-similar heart rate acceleration delivered via cardiac pacing vs. sham intervention in subjects at rest will be performed. The study population comprises subjects with guideline-directed medically managed severe left ventricular dysfunction due to ischemic or non-ischemic cardiomyopathy and an existing implantable cardioverter defibrillator or biventricular implantable cardioverter defibrillator. The purpose of the study is to understand how the heart rate pattern of exercise contributes to the considerable cardiac conditioning effects of exercise and estimate whether the pacing approach may have translational clinical applicability. Fifty-two subjects will be randomized, single-blinded, to either the pacing intervention or a sham intervention which they will receive once daily, 3 days/week for 6 weeks. Baseline symptoms and clinical test results will be compared to the same measures at 2 weeks, 4 weeks and 6 weeks of intervention/sham and at 3 months and one-year post-intervention. The primary endpoint will be the change in left ventricular ejection fraction from baseline in intervention vs. sham groups (mixed effects linear regression with time and treatment arm as fixed effects and pre-specified covariates of sex and cardiomyopathy type as random effects). Secondary endpoints will include changes in quality of life, 6-minute walk distance, cardiopulmonary exercise test (CPET) measures, daily activity and major adverse cardiac events (MACE) at 3 and 12 months between pacing and sham groups. A "dose-response" analysis of outcomes at 2, 4, and 6 weeks of the intervention vs. sham compared with baseline will be performed.