51 research outputs found
New insights about the putative role of myokines in the context of cardiac rehabilitation and secondary cardiovascular prevention.
Exercise training prevents the onset and the development of many chronic diseases, acting as an effective tool both for primary and for secondary prevention. Various mechanisms that may be the effectors of these beneficial effects have been proposed during the past decades: some of these are well recognized, others less. Muscular myokines, released during and after muscular contraction, have been proposed as key mediators of the systemic effects of the exercise. Nevertheless the availability of an impressive amount of evidence regarding the systemic effects of muscle-derived factors, few studies have examined key issues: (I) if skeletal muscle cells themselves are the main source of cytokine during exercise; (II) if the release of myokines into the systemic circulation reach an adequate concentration to provide significant effects in tissues far from skeletal muscle; (III) what may be the role carried out by muscular cytokine regarding the well-known benefits induced by regular exercise, first of all the anti-inflammatory effect of exercise. Furthermore, a greater part of our knowledge regarding myokines derives from the muscle of healthy subjects. This knowledge may not necessarily be transferred per se to subjects with chronic diseases implicating a direct or indirect muscular dysfunction and/or a chronic state of inflammation with persistent immune-inflammatory activation (and therefore increased circulating levels of some cytokines): cachexia, sarcopenia due to multiple factors, disability caused by neurological damage, chronic congestive heart failure (CHF) or coronary artery disease (CAD). A key point of future studies is to ascertain how is modified the muscular release of myokines in different categories of unhealthy subjects, both at baseline and after rehabilitation. The purpose of this review is to discuss the main findings on the role of myokines as putative mediators of the therapeutic benefits obtained through regular exercise in the context of secondary cardiovascular prevention
Role of regular physical activity in neuroprotection against acute ischemia
One of the major obstacles that prevents an effective therapeutic intervention against ischemic stroke is the lack of neuroprotective agents able to reduce neuronal damage; this results in frequent evolution towards a long-term disability with limited alternatives available to aid in recovery. Nevertheless, various treatment options have shown clinical efficacy. Neurotrophins such as brain-derived neurotrophic factor (BDNF), widely produced throughout the brain, but also in distant tissues such as the muscle, have demonstrated regenerative properties with the potential to restore damaged neural tissue. Neurotrophins play a significant role in both protection and recovery of function following neurological diseases such as ischemic stroke or traumatic brain injury. Unfortunately, the efficacy of exogenous administration of these neurotrophins is limited by rapid degradation with subsequent poor half-life and a lack of blood–brain-barrier permeability. Regular exercise seems to be a therapeutic approach able to induce the activation of several pathways related to the neurotrophins release. Exercise, furthermore, reduces the infarct volume in the ischemic brain and ameliorates motor function in animal models increasing astrocyte proliferation, inducing angiogenesis and reducing neuronal apoptosis and oxidative stress. One of the most critical issues is to identify the relationship between neurotrophins and myokines, newly discovered skeletal muscle-derived factors released during and after exercise able to exert several biological functions. Various myokines (e.g., Insulin-Like Growth Factor 1, Irisin) have recently shown their ability to protects against neuronal injury in cerebral ischemia models, suggesting that these substances may influence the degree of neuronal damage in part via inhibiting inflammatory signaling pathways. The aim of this narrative review is to examine the main experimental data available to date on the neuroprotective and anti-ischemic role of regular exercise, analyzing also the possible role played by neurotrophins and myokines
New Insights in Prevention and Treatment of Cardiovascular Disease
Cardiovascular (CV) disease (CVD) is still a major cause of morbidity and mortality in many countries in Europe although considerable efforts have been made in recent decades
to address this disease in an even more “comprehensive” approac
Cardiac remodeling according to the nocturnal fall of blood pressure in hypertensive subjects: The whole assessment of cardiac abnormalities in non-dipper subjects with arterial hypertension (wacanda) study
Objective: Several epidemiological studies suggest that the preservation of the physiological circadian rhythm of blood pressure or its disruption affects the extent of the organ damage developed by the patient. If we classify the circadian rhythm of blood pressure into four nocturnal profiles, significant differences emerge in terms of organ damage burden and prognosis: reverse dippers have the worst prognosis while dippers and mild dippers fall into an intermediate risk range. The risk profile of extreme dippers is still debated, and the available data are very conflicting and inconclusive. Starting from this gap of knowledge, we aimed to evaluate, retrospectively, in a cohort of hypertensive subjects, the degree of cardiac involvement in relation to the different nocturnal blood pressure profiles. Methods: We retrospectively evaluated 900 patients with essential hypertension, of whom 510 met our study criteria. We graded the 510 patients in relation to the percentage of reduction in mean systolic blood pressure (SBP) at night-time compared with day-time, considering this as a continuous variable, and then compared the extreme quintiles with each other and with the middle quintile (considered as reference). Results: Patients with less (or no) reduction in nocturnal SBP (reverse dipper) showed a higher level of organ damage and comorbidities. With regard to echocardiographic indexes, patients with maximum nocturnal pressure reduction (extreme dipper) showed a lower level of remodeling and/or impairment of E/e’ ratio, Right Atrium Area, Basal Right Ventricular Diameter, Inferior Vena Cava Average Diameter, and Tricuspidal Anular Plane Systolic Excursion compared also with hypertensive patients with a physiological nocturnal pressure reduction, even after correction for the main confounders. Conclusions: These data suggest that extreme dippers may constitute the subgroup of hypertensive patients with the lowest 24-h pressure load and, therefore, less cardiac remodeling
Feasibility study of adhesive bonding reinforcement by electrospun nanofibers
Abstract In previous works, the authors showed that the interleaving of an electrospun nylon nanofibrous mat at the interface between adjacent plies of a composite laminate increases the delamination strength. In particular, the nanomat acts a net-like reinforcing web, enabling a ply-to-ply bridging effect. This reinforcing property of the nanomats can be potentially used in other applications which need to improve the fracture resistance of interfaces, such as adhesive bonding. The present work analyses the feasibility of an electrospun polymeric nanomat as adhesive carrier and reinforcing web in industrial bonding. Thus the adhesive is used to pre-impregnate a nylon nanofibrous mat that is then placed at the interface between two metal pieces and then cured. The aim of the work is first to assess the effectiveness of this procedure, by comparison of the mode-I fracture toughness measured with DCB (Double Cantilever Beam) tests with and without the reinforcement in the adhesive layer. For this purpose, a 2024-T3 aluminum alloy will be bonded using a general purpose, one-part epoxy resin with low viscosity
Development of a workflow for the virtual optimization of a nanofiber-interleaved composite laminate subjected to impact loading
Delamination is one of most common failure mechanisms for composite materials. By interleaving nanofibers between laminate plies, the authors showed that it is possible to control the interlaminar fracture toughness. In particular, either a toughening or an embrittlement of the interface could be obtained by varying fibre diameter, fiber arrangement (random, aligned) and mat thickness. The modification induced by the nanomat can be therefore exploited in order to tailor the delamination strength of the laminate. The aim of this work is to identify a way to optimize the impact strength of a composite laminate with interleaved nanomats with respect to the maximization of the energy dissipated by delamination under impact. Impact damage is simulated using the Finite Element Method (FEM) with the Abaqus software. Cohesive elements are placed at the interfaces between groups of plies with different orientation of a plain weave composite laminate. Each interface can be assigned three different cohesive properties. The cohesive zone properties of virgin and nanomodified interfaces were identified in a previous work. The optimization workflow took into account also the possibility of changing the initial ply orientation. A multiobjective optimization was run for the counteracting objectives of max damage-dissipated energy and minimum decrease of composite stiffness
Prevalence of arterial hypertension and characteristics of nocturnal blood pressure profile of asthma patients according to therapy and severity of the disease: The bada study
Background: several studies report an increased risk for asthmatic subjects to develop arterial hypertension and the relationship between these two diseases, frequently co-existing, still has some unclear aspects. Methods: The BADA (blood pressure levels, clinical features and markers of subclinical cardiovascular damage of asthma patients) study is aimed to evaluate the prevalence of the cardiovascular comorbidities of asthma and their impact on the clinical outcome. The main exclusion criteria were the presence of other respiratory diseases, current smoking, any contraindication to ambulatory blood pressure monitoring (ABPM). Results: The overall percentage of asthmatics having also hypertension was 75% (30 patients) vs 45% (18 patients) of the control group (p: 0.012). Reduced level of FEV1 (but not inhaled steroid therapy) was associated to newlydiagnosed hypertension (p: 0.0002), higher day SBP levels (p: 0.003), higher day DBP levels (p: 0.03), higher 24 h-SBP levels (p: 0.005) and higher 24h-DBP levels (p: 0.03). The regression analysis performed taking into account sex, age, diabetes, fasting glucose, and body mass index confirms the independent role played by asthma: odds ratio (OR): 3.66 (CI: 1.29–11.1). Conclusions: hypertension is highly prevalent in asthma; the use of ABPM has allowed the detection of a considerable number of unrecognized hypertensives
Development of a workflow for the virtual optimization of a nanofiber-interleaved composite laminate subjected to impact loading
Delamination is one of most common failure mechanisms for composite materials. By interleaving nanofibers between laminate plies, the authors showed that it is possible to control the interlaminar fracture toughness. In particular, either a toughening or an embrittlement of the interface could be obtained by varying fibre diameter, fiber arrangement (random, aligned) and mat thickness. The modification induced by the nanomat can be therefore exploited in order to tailor the delamination strength of the laminate. The aim of this work is to identify a way to optimize the impact strength of a composite laminate with interleaved nanomats with respect to the maximization of the energy dissipated by delamination under impact. Impact damage is simulated using the Finite Element Method (FEM) with the Abaqus software. Cohesive elements are placed at the interfaces between groups of plies with different orientation of a plain weave composite laminate. Each interface can be assigned three different cohesive properties. The cohesive zone properties of virgin and nanomodified interfaces were identified in a previous work. The optimization workflow took into account also the possibility of changing the initial ply orientation. A multiobjective optimization was run for the counteracting objectives of max damage-dissipated energy and minimum decrease of composite stiffness
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