Experimental Exposure to Air Pollutants and Sympathetic Nerve Activity in Human Subjects
- Conditions
- Cardiovascular Morbidity
- Interventions
- Other: ultrafine particlesOther: ultrafine particles and ozoneOther: clean air
- Registration Number
- NCT01914783
- Lead Sponsor
- Hannover Medical School
- Brief Summary
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.
- Detailed Description
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.
Recruitment & Eligibility
- Status
- UNKNOWN
- Sex
- All
- Target Recruitment
- 30
- Elderly man or postmenopausal woman older than 50 years of age.
- Signed written informed consent.
- Smoker.
- Cardiovascular and/or pulmonary disease.
- Medication with relevant impact on autonomic system function, e. g. norepinephrine reuptake inhibitors. Stable medication with slight to moderate autonomic effects is tolerable.
- Subject is the investigator or any sub-investigator, research assistant, pharmacist, study coordinator, other staff or relative thereof directly involved in the conduct of the protocol.
- Mental condition rendering the subject unable to understand the nature, scope, and possible consequences of the study.
- Subject unlikely to comply with protocol, e. g. uncooperative attitude or unlikelihood of completing the study.
- Known hypersensitivity to ozone.
- History of drug or alcohol abuse. Particles Study - Protocol version: October 19, 2012 14
- Blood donation of more than 500 mL during the previous 3 months.
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description ultrafine particles 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. ultrafine particles and ozone ultrafine particles and ozone 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. clean air clean air 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.
- Primary Outcome Measures
Name Time Method Muscle sympathetic nerve activity (MSNA) 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone 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.
- Secondary Outcome Measures
Name Time Method MSNA burst incidence 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone Change of MSNA expressed as bursts/100 heart beats.
total MSNA 2.5 hours after exposure to clean air, to ultrafine particles, or to a combination of ultrafine particles and ozone Change of MSNA expressed as burst area/min.
Trial Locations
- Locations (1)
Hannover Medical School
🇩🇪Hannover, Germany