An interventional study of ultrafine particles and ultrafine particles and ozone in Cardiovascular Morbidity, sponsored by Hannover Medical School. Status unknown at 1 site in Germany. Open to participants aged 50 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2013-08-02.
Sponsored by Hannover Medical School · Not applicable, Interventional, and Supportive care
The primary hypothesis of the study is that in healthy elderly subjects experimental exposure to air pollutants increases sympathetic nervous system activity compared with sham (clean air) exposure. The secondary hypothesis of the study is that combined experimental exposure to air pollutants (particles + ozone) increases sympathetic nervous system activity to a greater extent than does the exposure to particles alone.
In a randomized, double-blind, and cross-over fashion, the participants will be exposed to clean air, ultrafine particles, or ultrafine particles and ozone in an exposure chamber. The investigators will determine blood pressure, heart rate, respiration as well as cardiac output and directly record sympathetic vasomotor tone using the microneurography technique. To elucidate the underlying mechanisms through which particles and ozone affect the autonomic nervous system, the investigators will assess the local and systemic inflammatory response as well as the changes in neurotrophic factors in sputum and blood. In addition, the activation of inflammatory cells in sputum and blood will be analyzed at different points in time after exposures. Changes in sympathetic activity will be correlated with the degree of airway inflammation and oxidative stress assessed in induced sputum and blood. This study will provide important insight in the mechanisms through which air pollution, particularly ultrafine particle exposure, increases cardiovascular risk in human subjects and generate a human model for mechanistic and therapeutic studies.
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Subjects will be exposed to ultrafine particles for three hours in an exposure chamber. During that time participants will perform intermittent bicycle ergometer training. Training intensity is adjusted individually to increase ventilation to 20 l/min/m². During exposure, heart rate will be monitored continuously via ECG. Blood pressure will be measured every 15 minutes. Ultrafine elemental carbon black particles are generated using a commercially available electric spark generator. Particle number, mass, and size distribution will be monitored during exposure.
Other: ultrafine particles
Subjects will be exposed to ultrafine particles for three hours in an exposure chamber. During that time participants will perform intermittent bicycle ergometer training. Training intensity is adjusted individually to increase ventilation to 20 l/min/m². During exposure, heart rate will be monitored continuously via ECG. Blood pressure will be measured every 15 minutes. Ultrafine elemental carbon black particles are generated using a commercially available electric spark generator. Particle number, mass, and size distribution will be monitored during exposure.Ozone is generated from medical oxygen in order to maintain a concentration of 250 ppb.
Other: ultrafine particles and ozone
Subjects will be exposed to clean air for three hours in an exposure chamber controlled for temperature, humidity, and gas/particle composition. During that time they will perform intermittent bicycle ergometer training for 15 minutes alternating with 15 minutes rest. Training intensity is adjusted individually to increase ventilation to 20 l/min/m². During exposure, heart rate will be monitored continuously via ECG. The blood pressure will be measured in time intervals of 15 minutes.
Other: clean air
exposure to ultrafine particles
exposure to ultrafine particles and ozone
Exposure to clean air.
Muscle sympathetic nerve activity (MSNA)
Change of sympathetic vasoconstrictor nerve activity directed to skeletal muscle expressed as sympathetic bursts per minute. The primary hypothesis of the study is that in healthy elderly subjects experimental exposure to air pollutants increases sympathetic nervous system activity compared with sham (clean air) exposure.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
MSNA burst incidence
Change of MSNA expressed as bursts/100 heart beats.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
total MSNA
Change of MSNA expressed as burst area/min.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Blood pressure
Change of blood pressure in mmHg.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Heart rate
Change of heart rate in beat per minute.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Cardiac output
Change of cardiac output in l/min.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Total peripheral resistance
Change in total peripheral resistance expressed as dyn\*s/cm\^5.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Heart rate variability.
Change in heart rate variability parameters in the time and frequency domain.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Plasma norepinephrine concentration
Change of plasma norepinephrine in ng/l.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Plasma renin concentration
Change of plasma renin concentration in
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Baroreflex sensitivity
Change in baroreflex sensitivity expressed as ms/mmHg.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Inflammation parameters
Change of the percentage of neutrophils in induced sputum.
Time frame: 3.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Oxidative stress parameters
Change of plasma malondialdehyde(MDA)concentration.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Correlation between inflammation, oxidative stress and cardiovascular regulation
Correlation coefficients between changes in parameters for inflammation and oxidative stress with changes in cardiovascular parameters.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Forced expiratory volume in one second (FEV1)
Change in FEV1 in l
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Forced vital capacity (FVC)
Change in FVC in l.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
Percentage of neutrophils in peripheral blood
Change of percentage of neutrophils in peripheral blood.
Time frame: 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone
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Hannover Medical School