Active clinical trials for "Atherosclerosis"

Macrophages can exhibit distinct phenotypes and functions in response to stimuli and can polarize into one of three distinct phenotypes: a pro-inflammatory (M1), an anti-inflammatory pro-tissue (M2) and metabolically-activated (MMe) macrophage phenotypes. Thirty-six healthy volunteers were recruited and randomized into one of three macronutrient intake groups (glucose, lipids, proteins). This study measured the effects of macronutrient intake on the macrophage differentiation.

A pilot study to assess feasibility of methods of an observer-blinded randomised controlled trial of the effect of vitamin D supplementation in Chronic Kidney Disease and low vitamin D levels on markers of vascular function (Flow Mediated Dilatation of Brachial Artery), vascular structure (Carotid Intima Media Thickness) and Immune Regulation (frequencies of CD4+CD28null T lymphocytes ad Regulatory T lymphocytes).

Obstructive sleep apnea (OSA) syndrome is associated with increased vascular dysfunction and atherosclerosis. Especially, it has been shown that OSA associated intermittent hypoxia represents a pro inflammatory stimulus resulting in macrophage polarization. Protein tyrosine phosphatase 1B (PTP1B) is a negative regulator of insulin signaling pathways involved in atherosclerosis. It has been shown that myeloid PTP1B deficiency protects against atherosclerosis. As hypoxia has also been shown to increase PTP1B expression and activity, this study will evaluate the myeloid PTP1B expression and activity in patients with OSA as compared to controls and will investigate myeloid PTP1B involvement in the vascular pro inflammatory precess described in OSA.

This study aims at evaluating the prevalence of Clonal Hematopoiesis of Indeterminate Potential (CHIP) in patients over 75 presenting with a first cardio-vascular event (CVE). The investigators will also determine if CHIPs are more frequent in this population compared to a control cohort without CVE. An association between CHIP, a systemic inflammation and increased atherosclerosis will also be assessed.

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.

The reverse cholesterol transport (RCT) pathway, which involves the centripetal movement of free cholesterol from peripheral tissues, including the vessel wall, to the liver represent the primary mechanism by which HDL protects against atherosclerosis and by which it may induce plaque regression. Recent data reveal that the capacity of HDL to efflux cholesterol from macrophages, a metric of HDL function reflecting the initial step of the RCT, is clinically relevant, displaying a strong inverse association with both carotid intima-media thickness and the severity of angiographic CAD; such observations were independent of HDL-C levels. In human, the Cholesteryl Ester Transfer Protein (CETP), represents a key protein of the RCT pathway and mediates redistribution of neutral lipids between lipoproteins, has been identified as a potential therapeutic target against atherosclerosis. It is known that CETP activity correlates with HDL-C levels and represents a key modulator of the ability of whole plasma to mediate free cholesterol efflux from human macrophages. Recent studies showed that 23% of endogenous plasma CETP activity variability is explained by plasma LDL-C (12.0%), HDL-C (6.4%) and TG (4.4%) whereas sex and BMI accounted together for only 0.7% of its variability. Scoring patients for cardiovascular risk on the basis of their plasma lipid levels (TC, TG, LDL-C and HDL-C), revealed that patients with high cardiovascular risk (score ≥3) displayed a mean endogenous plasma CETP activity above 34%. Therefore plasma CETP activity represents a potent indicator of cardiovascular risk in patients with metabolic disorders since it integrates major independent risk factors. The objective of this study is to decipher the relationship between CETP, HDL efflux capacity and the development of atherosclerosis in humans in order to identify CETP as a potent biomarker of atherosclerosis distribution.

The aim of this study is to investigate whether the non-invasive ultrasound method for assessment of coronary blood flow, transthoracic Doppler echocardiography-coronary flow reserve (TTDE-CFR), can be used to measure drug effects.

Atherosclerosis is a condition that occurs when fatty deposits build up along the inner walls of arteries. This study will examine the effectiveness of a combination of cholesterol-lowering medications at decreasing the fat content of atherosclerotic deposits in people who have coronary artery disease or carotid artery disease.

Alirocumab is an injectable treatment for elevated blood cholesterol. The hypothesis of this study is that it also increases cholesterol excretion from the body into the stool, a process sometimes called reverse cholesterol transport. A cholesterol metabolic study will be done before and after 6 weeks of alirocumab treatment. If alirocumab increases reverse cholesterol transport, it is possible that this action provides additional protection from cardiovascular disease.

Glucocorticoids (GCs) are a class of endogenous steroid hormones produced by the adrenal glands and controlled by the hypothalamic-pituitary-adrenal axis (HPA). One of the mechanisms of their action is achieved through ligand-receptor attachment to a class of cytosolic steroid hormone receptors termed Glucocorticoid Receptors (GRs). The formed ligand-receptor complex is a transcription factor involved in gene activation of anti-inflammatory products or repression of pro-inflammatory products [1]. Synthetic forms of GCs are a group of anti-inflammatory and immunosuppressive medications (e.g. Prednisone) that are widely used in clinical practice to treat inflammatory diseases (e.g. Rheumatoid Arthritis, Vasculitis, Asthma). The effectiveness of this class of drugs is limited by numerous adverse effects that include, but not limited to, insulin resistance, glucose intolerance, dyslipidemia, and hypertension, all of which are well known risk factors for cardiovascular diseases (CVD) [2,3]. Furthermore, recent research suggest that inflammation has a key role in development of CVD and can predict prognosis [4]. Inflammatory cells have an important role in the development of atherosclerotic lesion in the arteries. Blood monocyte-derived macrophages are involved in this process, and they infiltrate the lesion where they take up various forms of lipids (cholesterol - rich LDL, and oxidized LDL) as well as triglycerides - rich VLDL), followed by the formation of lipid-laden foam cells, the hallmark of early atherogenesis. Inflammatory cells and molecules as well as proteolytic enzymes secreted from inflammatory cells in the atherosclerotic lesion, have a central role in destabilizing the plaque (vulnerable plaque) leading to its rupture, which, in turn, induces thrombosis, and initiating acute coronary events [4,5]. Based on our understanding of the involvement of inflammation in the early development of atherosclerotic lesion, and our experience with the anti-inflammatory effects of synthetic GCs, a hypothesis emerged suggesting this class of drugs as a way to inhibit early atherosclerotic plaque formation, and to attenuate CVDs [6]. Research results in this field are surprising because while glucocorticoids treatment in humans increase the risk of CVDs [6,7,8,9], animal models shows the opposite, atheroprotection was shown in rabbits [10,11,12] and mice [13,14,15]. This paradox may be explained partially by the fact that clinical studies in this field are mainly conducted in patients with predisposing factors to develop CVD, either because of pre-existing traditional risk factors like Diabetes and Hyperlipidemia, or because of the pre-existing medical condition they are being treated for with GCs (e.g. Rheumatoid Arthritis). Mechanism based research to study the effects of GCs on atherogenesis, without confounding factors, is lacking. Only few studies were performed on GCs in healthy subjects but none of them explored their effects on foam cell formation [16,17]. Our study thus aims to further our understanding of the role of specific glucocorticoid, prednisone, in the process of atherogenesis. In order to achieve that we plan to study the following: 1. The effects of five days of treatment with prednisone on serum lipid concentration and oxidative stress. 2. an Ex-vivo study is planned where the serum of healthy human subjects treated with Prednisone, will be introduced to J774A.1 murine macrophage-like cell line, a well-studied macrophage foam cell formation model.