Sympathetic activation by lower body negative pressure decreases kidney perfusion without inducing hypoxia in healthy humans

Purpose There is ample evidence that systemic sympathetic neural activity contributes to the progression of chronic kidney disease, possibly by limiting renal blood flow and thereby inducing renal hypoxia. Up to now there have been no direct observations of this mechanism in humans. We studied the effects of systemic sympathetic activation elicited by a lower body negative pressure (LBNP) on renal blood flow (RBF) and renal oxygenation in healthy humans. Methods Eight healthy volunteers (age 19-31 years) were subjected to progressive LBNP at - 15 and - 30 mmHg, 15 min per level. Brachial artery blood pressure was monitored intermittently. RBF was measured by phase-contrast MRI in the proximal renal artery. Renal vascular resistance was calculated as the MAP divided by the RBF. Renal oxygenation (R2*) was measured for the cortex and medulla by blood oxygen level dependent (BOLD) MRI, using a monoexponential fit. Results With a LBNP of - 30 mmHg, pulse pressure decreased from 50 +/- 10 to 43 +/- 7 mmHg; MAP did not change. RBF decreased from 1152 +/- 80 to 1038 +/- 83 mL/min to 950 +/- 67 mL/min at - 30 mmHg LBNP (p = 0.013). Heart rate and renal vascular resistance increased by 38 +/- 15% and 23 +/- 8% (p = 0.04) at - 30 mmHg LBNP, respectively. There was no change in cortical or medullary R2* (20.3 +/- 1.2 s(-1) vs 19.8 +/- 0.43 s(-1); 28.6 +/- 1.1 s(-1) vs 28.0 +/- 1.3 s(-1)). Conclusion The results suggest that an increase in sympathetic vasoconstrictor drive decreases kidney perfusion without a parallel reduction in oxygenation in healthy humans. This in turn indicates that sympathetic activation suppresses renal oxygen demand and supply equally, thus allowing adequate tissue oxygenation to be maintained.Cardiovascular Aspects of Radiolog

Liposomal prednisolone promotes macrophage lipotoxicity in experimental atherosclerosis

Atherosclerosis is a lipid-driven inflammatory disease, for which nanomedicinal interventions are under evaluation. Previously, we showed that liposomal nanoparticles loaded with prednisolone (LN-PLP) accumulated in plaque macrophages, however, induced proatherogenic effects in patients. Here, we confirmed in low-density lipoprotein receptor knockout (LDLr−/−) mice that LN-PLP accumulates in plaque macrophages. Next, we found that LN-PLP infusions at 10 mg/kg for 2 weeks enhanced monocyte recruitment to plaques. In follow up, after 6 weeks of LN-PLP exposure we observed (i) increased macrophage content, (ii) more advanced plaque stages, and (iii) larger necrotic core sizes. Finally, in vitro studies showed that macrophages become lipotoxic after LN-PLP exposure, exemplified by enhanced lipid loading, ER stress and apoptosis. These findings indicate that liposomal prednisolone may paradoxically accelerate atherosclerosis by promoting macrophage lipotoxicity. Hence, future (nanomedicinal) drug development studies are challenged by the multifactorial nature of atherosclerotic inflammation

The challenge of choosing in cardiovascular risk management

Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. For many years guidelines have listed optimal preventive therapy. More recently, novel therapeutic options have broadened the options for state-of-the-art CV risk management (CVRM). In the majority of patients with CVD, risk lowering can be achieved by utilising standard preventive medication combined with lifestyle modifications. In a minority of patients, add-on therapies should be considered to further reduce the large residual CV risk. However, the choice of which drug combination to prescribe and in which patients has become increasingly complicated, and is dependent on both the absolute CV risk and the reason for the high risk. In this review, we discuss therapeutic decisions in CVRM, focusing on (1) the absolute CV risk of the patient and (2) the pros and cons of novel treatment options.Cardiolog

Identification and diagnosis of patients with familial chylomicronaemia syndrome (FCS)

Familial chylomicronaemia syndrome (FCS) is a rare, inherited disorder characterised by impaired clearance of triglyceride (TG)-rich lipoproteins from plasma, leading to severe hypertriglyceridaemia (HTG) and a markedly increased risk of acute pancreatitis. It is due to the lack of lipoprotein lipase (LPL) function, resulting from recessive loss of function mutations in the genes coding LPL or its modulators. A large overlap in the phenotype between FCS and multifactorial chylomicronaemia syndrome (MCS) contributes to the inconsistency in how patients are diagnosed and managed worldwide, whereas the incidence of acute hypertriglyceridaemic pancreatitis is more frequent in FCS. A panel of European experts provided guidance on the diagn

Efficacy and Safety of Mipomersen, an Antisense Inhibitor of Apolipoprotein B, in Hypercholesterolemic Subjects Receiving Stable Statin Therapy

Objectives The aim of this study was to evaluate the efficacy and safety of mipomersen in hypercholesterolemic subjects taking stable statin therapy. Background Mipomersen is an apolipoprotein (apo) B synthesis inhibitor that has demonstrated significant reductions in apo B and low-density lipoprotein (LDL) cholesterol in Phase 1 clinical trials in healthy volunteers. Methods A randomized, placebo-controlled, dose-escalation Phase 2 study was designed to evaluate the effects of mipomersen in hypercholesterolemic subjects taking stable statin therapy. Seventy-four subjects were enrolled sequentially into 1 of 6 dose cohorts at a 4:1 (active/placebo) ratio. Subjects received 7 doses of 30 to 400 mg over 5 weeks in the first 5 cohorts and 15 doses of 200 mg over 13 weeks in the sixth cohort. Pre-specified end points included percentage change from baseline in apo B and LDL cholesterol. Safety was assessed with laboratory test results and by the incidence and severity of adverse events. Results The apo B and LDL cholesterol were reduced by 19% to 54% and 21% to 52%, respectively, at doses of 100 mg/week mipomersen and higher in the 5-week treatment cohorts. Efficacy seemed to increase upon treatment for 13 weeks at a dose of 200 mg/week. Injection site reactions (mild to moderate erythema [90%]) and hepatic transaminase increases (17%) were the most common adverse events, leading to discontinuation in 2 subjects and 1 subject, respectively. In the 13-week treatment cohort, 5 of 10 subjects (50%) had elevations >= 3x the upper limit of normal, 4 of which persisted on 2 consecutive occasions. Conclusions Mipomersen might hold promise for treatment of patients not reaching target LDL cholesterol levels on stable statin therapy. Further studies are needed to address the mechanisms and clinical relevance of transaminase changes after mipomersen administration. (Dose-Escalating Safety Study in Subjects on Stable Statin Therapy; NCT00231569) (J Am Coll Cardiol 2010;55:1611-8) (C) 2010 by the American College of Cardiology FoundationVascular Biology and Interventio

Monocyte-chemoattractant protein-1 levels in human atherosclerotic lesions associate with plaque vulnerability

OBJECTIVE: To determine whether MCP-1 (monocyte chemoattractant protein 1) levels in human atherosclerotic plaques associate with plaque vulnerability features. APPROACH AND RESULTS: We measured MCP-1 levels in human atherosclerotic plaque samples from 1199 patients in the AtheroEXPRESS Biobank who underwent endarterectomy for treatment of carotid stenosis. We explored associations with histopathologic and molecular features of plaque vulnerability, clinical plaque manifestations, and vascular events up to 3 years after endarterectomy. Following adjustments for age, sex, and vascular risk factors, MCP-1 plaque levels were associated with histopathologic markers of plaque vulnerability (large lipid core, low collagen content, high macrophage burden, low smooth muscle cell burden, intraplaque hemorrhage) and with a composite vulnerability index (range 0-5, β per SD increment in MCP-1, 0.42 [95% CI, 0.30-0.53], P=5.4×10−13). We further found significant associations with higher plaque levels of other chemokines and proinflammatory molecules and markers of neovascularization and matrix turnover. When exploring clinical plaque instability, MCP-1 plaque levels were higher among individuals with symptomatic plaques as compared with those with asymptomatic plaques (odds ratio per SD increment in MCP-1, 1.36 [95% CI, 1.09-1.69]). MCP-1 levels were further associated with a higher risk of periprocedural major adverse vascular events and strokes occurring in the first 30 days after plaque removal. CONCLUSIONS: Higher MCP-1 plaque levels are associated with histopathologic, molecular, and clinical hallmarks of plaque vulnerability in individuals undergoing carotid endarterectomy. Our findings highlight a role of MCP-1 in clinical plaque instability in humans and complement previous epidemiological, genetic, and experimental studies supporting the translational perspective of targeting MCP-1 signaling in atherosclerosis