Vaping with Nicotine during Pregnancy Affects Aortic Structure and Function in Rat Offspring

Electronic cigarette (E-cig) use during pregnancy has grown in popularity due to the marketing of these devices as safer alternatives to traditional cigarettes. However, nicotine is a constituent in cigarettes that is cause for concern and is also present in a majority of E-cig devices. Little has been reported regarding the implications of E-cig use with nicotine during pregnancy on offspring health outcomes. This study tested the hypothesis that in-utero exposure to nicotine-containing E-cig aerosol would result in a wattage-dependent increase in vascular endothelial dysfunction and arterial stiffening that would persist throughout the lifespan of the offspring. Pregnant Sprague-Dawley rats were exposed to E-cig aerosol containing 50 mg/mL of nicotine at either 5- or 30-watts for the length of their gestation. Pups were aged out to 1-, 3-, 6-, and 12-months of age. Vascular structure was assessed through in-vivo pulse wave velocity (PWV) measurements on the left common carotid artery, and (following euthanasia) histological stains of elastin and collagen fibers of the abdominal aorta. Pulse wave velocity (PWV) was found to be significantly increased in the 30W group at 6- and 12-months compared to air controls. Elastin content was not statistically different between exposure groups at any timepoint. Vascular function was assessed through ex-vivo wire myography on the thoracic aorta. Endothelial dysfunction of the thoracic aorta was not found to be statistically different between exposure groups at the 1-, 3-, or 6-month timepoints. However, at the 12-month timepoint, exposed offspring did exhibit greater endothelial dysfunction than their nonexposed counterparts. These data imply that vaping with nicotine at a high wattage during pregnancy can induce structural and functional abnormalities in the blood vessels of adult offspring that are major risk factors for cardiovascular disease

Contribución a un enfoque no convencional de la función vascular periférica: estudio del impacto fisiológico del masaje en la circulación del miembro inferior

Massage is a long-known technique, applied with your hands for multiple purposes associated to health and well-being, but the demonstration of its physiological impact and mechanisms is still limited, and sometimes controversial or inconclusive. Some studies suggested a positive contribution of massage in pain modulation fatigue anxiety relief and stress control regardless of other underlying pathologies. Our main objective was to study the physiological impact of massage in the human lower limb and the involved adaptive mechanisms in previously selected and characterized healthy groups. We used well known reliable non-invasive optical techniques to register microcirculation events with total comfort and safety of participants - Laser Doppler flowmetry (LDF) and photoplethysmography (PPG). In addition, we also used the Wavelet transform (WT), applied to the decomposition of these signals. The present project involved 98 participants (32.6 ± 15.5 years) of both sexes, normotensive and without signs of vascular impairment and all procedures followed the principles of the Declaration of Helsinki (institutional Ethics Committee 03/2013.12). The massage protocol was evaluated in two of its variants in terms of the direction of application: ascending and descending, applied to one of the lower limbs previously randomized, with the other limb serving as control. The experimental massage procedure involved three phases of continuous recording with participants lying in supination - Phase I (baseline) for 10 minutes, Phase II, provocation (massage) for 5 minutes and Phase III, recovery for 10 minutes. Our project was structured in four milestones, the first being the definition of the experimental procedure, which allowed us to immediately observe that the perfusion impact of massage was observed in both limbs, despite being applied to only one of the limbs. The second milestone, in which we intended to deepen the data analysis, confirmed by correlation analysis of raw LDF and PPG signals the existence of significant proximity of these signals. In the third milestone, we confirm the adequacy of the chosen non-invasive measurement technologies and we verify that the average spectrum of the LDF and PPG signal profiles have different amplitudes. In the last milestone, we confirmed that massage involves more than a change in the local microcirculation that we named as the Prompt Adaptive Hemodynamic Response (PAHR) impacting the entire systemic cardiocirculatory hemodynamics. This answer was addressed in a complementary way in equally healthy individuals, but older, constituting the last manuscript of this collection. Here we demonstrate that, although responses here obtained are similar to those obtained in young participants, this PAHR is age dependent and therefore less obvious, suggesting its potential interest to be used as a clinical indicator. Based on the results obtained in these four milestones, we were able to substantiate the following main conclusions: 1 - that the experimental procedure we designed, proved to be rigorous, easily reproductible and totally adequate to the purposes of the study, while also ensuring total comfort and well-being of the participants. 2 - that the technologies chosen to evaluate microcirculation, namely LDF and PPG, proved to be suitable for the study, as the results allowed to quantitatively and accurately describe the peripheral microcirculation in vivo, under dynamic conditions such as those involved in massage, having been verified that the use of both technologies provides a more sustained analysis of the phenomena in question. 3 - that the massage maneuver when applied to the lower limb of young and healthy individuals, allows to increase the microcirculatory flow in the massaged lower limb, but also in the contralateral limb, being this effect, regardless of the direction in which the massage is applied, influencing the hemodynamics in general, affecting heart rate and blood pressure. 4 - that this hemodynamic response to massage that we identified in this study (PAHR), although similar, is clearly dependent on age

Fluid mechanics of Windkessel effect

Abstract We describe a mechanistic model of Windkessel phenomenon based on the linear dynamics of fluid-structure interactions. The phenomenon has its origin in an old-fashioned fire-fighting equipment where an air chamber serves to transform the intermittent influx from a pump to a more steady stream out of the hose. A similar mechanism exists in the cardiovascular system where blood injected intermittantly from the heart becomes rather smooth after passing through an elastic aorta. In existing haeodynamics literature, this mechanism is explained on the basis of electric circuit analogy with empirical impedances. We present a mechanistic theory based on the principles of fluid/structure interactions. Using a simple one-dimensional model, wave motion in the elastic aorta is coupled to the viscous flow in the rigid peripheral artery. Explicit formulas are derived that exhibit the role of material properties such as the blood density, viscosity, wall elasticity, and radii and lengths of the vessels. The current two-element model in haemodynamics is shown to be the limit of short aorta and low injection frequency and the impedance coefficients are derived theoretically. Numerical results for different aorta lengths and radii are discussed to demonstrate their effects on the time variations of blood pressure, wall shear stress, and discharge. Graphical Abstract A mechanistic analysis of Windkessel Effect is described which confirms theoretically the well-known feature that intermittent influx becomes continuous outflow. The theory depends only on the density and viscosity of the blood, the elasticity and dimensions of the vessel. Empirical impedence parameters are avoide