Autonomic dysfunction is very common in patients with dementia, and its presence might also help in differential diagnosis among dementia subtypes. Various central nervous system structures affected in Alzheimer's disease are also implicated in autonomic nervous system regulation, and it has been hypothesized that the deficit in central cholinergic function observed in Alzheimer's disease could likely lead to autonomic dysfunction. Several feasible tests can be used in clinical practice for the assessment of parasympathetic and sympathetic functions, especially in terms of cardiovascular autonomic modulation. In this review, we describe the different tests available and the evidence from the literature which indicate a definite presence of autonomic dysfunction in dementia at various degrees. Importantly, the recognition of dysautonomia, besides possibly being an early marker of dementia, would help prevent the disabling complications which increase the risk of morbidity, institutionalization, and mortality in these individuals.
Background: Epicardial adipose tissue (EAT) thickness and pro-inflammatory status has been shown to be associated with several cardiac diseases, including aortic stenosis (AS). Thus, cardiac visceral fat could represent a potential new target for drugs. In the present study we evaluate the effect of statin therapy on EAT accumulation and inflammation. Methods: Echocardiographic EAT thickness was assessed in 193 AS patients taking (n.87) and not taking (n.106) statins, undergoing cardiac surgery. To explore the association between statin therapy and EAT inflammation, EAT biopsies were obtained for cytokines immunoassay determination in EAT secretomes. An in vitro study was also conducted and the modulation of EAT and subcutaneous adipose tissue (SCAT) secretomes by atorvastatin was assessed in paired biopsies. Results: Statin therapy was significantly associated with lower EAT thickness (p b 0.0001) and with lower levels of EAT-secreted inflammatory mediators (p b 0.0001). Of note, there was a significant correlation between EAT thickness and its pro-inflammatory status. In vitro, atorvastatin showed a direct anti-inflammatory effect on EAT which was significantly higher compared to the SCAT response to statin incubation (p b 0.0001). Conclusions: The present study indicates a robust association between statin therapy and reduced EAT accumulation in patients with AS. The present data also suggest a direct relationship between EAT thickness and its inflammatory status, both modulated by statin therapy. The in vitro results support the hypothesis of a direct action of statins on EAT secretory profile. Overall our data suggest EAT as a potential new therapeutic target for statin therapy.
OBJECTIVEImpaired parasympathetic and sympathetic nervous system activity have been demonstrated in patients with diabetes mellitus (DM) and correlated with worse prognosis. Few data are available on the effect of DM on cardiac neuropathy in heart failure (HF). The aim of the current study was to assess cardiac sympathetic activity in HF patients with and without DM.RESEARCH DESIGN AND METHODSPatients with severe HF (n = 75), with (n = 37) and without DM (n = 38), and 14 diabetic patients with normal cardiac function underwent 123I meta-iodobenzylguanidine scintigraphy from which early and late heart-to-mediastinum (H/M) ratios were calculated. Clinical, echocardiographic, and biochemical data were measured.RESULTSDM compared with non-DM patients showed significantly lower early (1.65 ± 0.21 vs. 1.75 ± 0.21; P < 0.05) and late H/M ratios (1.46 ± 0.22 vs. 1.58 ± 0.24; P < 0.03). Early and late H/M were significantly higher in DM patients without HF (2.22 ± 0.35 and 1.99 ± 0.24, respectively) than HF patients with (P < 0.0001) and without (P < 0.0001) DM. In HF patients, an inverse correlation between early or late H/M ratio and hemoglobin A1c (HbA1c) (Pearson = −0.473, P = 0.001; Pearson = −0.382, P = 0.001, respectively) was observed. In DM, in multivariate analysis, HbA1c and ejection fraction remained significant predictors of early H/M; HbA1c remained the only significant predictor of late H/M. No correlation between early or late H/M and HbA1c was found in non-DM patients.CONCLUSIONSDiabetic patients with HF show lower cardiac sympathetic activity than HF patients not having DM or than DM patients with a similar degree of autonomic dysfunction not having HF. HbA1c correlated with the degree of reduction in cardiac sympathetic activity.
In heart failure (HF), exercise has been shown to modulate cardiac sympathetic hyperactivation which is one of the earliest features of neurohormonal derangement in this syndrome and correlates with adverse outcome. An important molecular alteration related to chronic sympathetic overstimulation in HF is represented by cardiac β-adrenergic receptor (β-AR) dysfunction. It has been demonstrated that exercise reverses β-AR dysfunction by restoring cardiac receptor membrane density and G-protein-dependent adenylyl cyclase activation. In particular, several evidence indicate that exercise reduces levels of cardiac G-protein coupled receptor kinase-2 (GRK2) which is known to be involved in both β1-AR and β2-AR dysregulation in HF. Similar alterations of β-AR system have been described also in the senescent heart. It has also been demonstrated that exercise training restores adrenal GRK2/α-2AR/catecholamine (CA) production axis. At vascular level, exercise shows a therapeutic effect on age-related impairment of vascular reactivity to adrenergic stimulation and restores β-AR-dependent vasodilatation by increasing vascular β-AR responsiveness and reducing endothelial GRK2 activity. Sympathetic nervous system overdrive is thought to account for >50% of all cases of hypertension and a lack of balance between parasympathetic and sympathetic modulation has been observed in hypertensive subjects. Non-pharmacological, lifestyle interventions have been associated with reductions in SNS overactivity and blood pressure in hypertension. Several evidence have highlighted the blood pressure lowering effects of aerobic endurance exercise in patients with hypertension and the significant reduction in sympathetic neural activity has been reported as one of the main mechanisms explaining the favorable effects of exercise on blood pressure control.
Rationale: It has been reported that epicardial adipose tissue (EAT) may affect myocardial autonomic function.Objective: The aim of this study was to explore the relationship between EAT and cardiac sympathetic nerve activity in patients with heart failure. Methods and Results:In 110 patients with systolic heart failure, we evaluated the correlation between echocardiographic EAT thickness and cardiac adrenergic nerve activity assessed by Conclusions:This study provides the first evidence of a direct correlation between increased EAT thickness and cardiac sympathetic denervation in heart failure. (Circ Res.
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