This study comprises a portion of a larger study designed to compare results of vascular function in non-smokers to vascular function in healthy smokers chronically exposed to nicotinized electronic cigarette aerosol versus conventional cigarettes.
Here, we 1) investigate the acute effects of non-nicotinized e-cigarette aerosol inhalation in nonsmokers in terms of blood-based markers of inflammation and oxidative stress, and 2) evaluate their association with hemodynamic-metabolic MRI parameters quantifying peripheral vascular reactivity, cerebrovascular reactivity, and aortic stiffness.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
31
16 two-second-long puffs from a non-nicotinized electronic cigarette.
University of Pennsylvania Perelman School of Medicine
Philadelphia, Pennsylvania, United States
Inflammatory Blood-Based Biomarkers
Post-vaping inflammation monitored by changes in an integrated cluster of blood-based biomarkers from serum/plasma of non-smoking healthy participants quantified at 0 and 120 min post-inhalation. The cluster consisted of: CRP, sICAM-1 in serum and HMGB1, ASC in plasma assayed using ELISA and quantified using absorbance-concentration curves generated by the manufacturers' standards; nitric oxide metabolites (nitrate + nitrite, NOx) in serum assayed with a nitrate/nitrite kit using a colorimetric standard provided by the manufacturer; reactive oxygen species (ROS) was quantified by using immortalized human pulmonary microvascular endothelial cells plated, prepared with serum, labeled with ROS dye and imaged confocal fluorescence microscopy. The outcome measure was expressed as fold increase over pre-vaping values.
Time frame: Participant blood draws occurred at two time points: 1) pre-vaping, 2) 120 minutes post-vaping. Inflammation index is calculated from the fold change in biomarker values over pre-vaping values
Acute Change in Aortic Pulse Wave Velocity Post-vaping
Central arterial stiffness was assessed using aortic pulse-wave velocity (PWV), a biomarker of aortic stiffness calculated by measuring the velocity of a pulse wave between two points in the same artery. A higher aortic pulse wave velocity equates to a stiffer aorta. In each participant, aortic PWV was quantified, pre- and post-vaping, by dividing the path length of the aortic arch determined from a oblique sagittal image, by the transit time of the pulse pressure wave. Measurements obtained pre-vaping were compared to those obtained post-vaping.
Time frame: PWV calculation occurred at two time points: 1) pre-vaping, 2) Fifteen minutes post-vaping.
Change in Femoral Artery Flow-Mediated Dilation Post-Vaping
Degree of dilation (% change in cross-sectional area) of femoral artery during hyperemia (the transient increase in blood flow velocity) after e-cigarette vaping as compared to before e-cigarette vaping.
Time frame: Flow mediated dilation calculation occurred at two time points: 1) pre-vaping, 2) 40 minutes post-vaping.
Change in Washout Time Post-Vaping
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Transit time of desaturated capillary blood from tissue to the imaging location after e-cigarette vaping
Time frame: Washout time calculation occurred at two time points: 1) pre-vaping, and 2) 40 minutes post-vaping
Change in Upslope Post-Vaping
Tissue oxygen resaturation rate after e-cigarette vaping.
Time frame: Upslope was calculated at two time points: 1) pre-vaping, and 2) 40 minutes post-vaping
Change in Overshoot Post-Vaping
Degree of overcompensatory effect post-vaping in the supply of oxygen after ischemia.
Time frame: Overshoot was calculated at two time points: 1) pre-vaping, and 2) 40 minutes post-vaping.
Change in Breath Hold Index Post-Vaping
Rate of increase in blood flow velocity in the superior sagittal sinus from intermittent volitional apnea.
Time frame: Breath hold index was calculated at two time points: 1) pre-vaping, 2) five minutes post-vaping.