Effect of Woodsmoke on Vascular Function (FIREWOOD)

• Ex-vivo thrombus formation using the Badimon chamber [ Time Frame: 2 hours after exposure ] [ Designated as safety issue: No ]
• Plasma t-PA and PAI concentrations following infusion of bradykinin [ Time Frame: During forearm study, 4-6hours after exposure ] [ Designated as safety issue: No ]

Exposure to air pollution is a well established risk factor for the development of heart disease. Firefighters are exposed to excess air pollution in the form of wood smoke during the extinguishing of forest or woodland fires. Heart attacks in on-duty firefighters have been linked to specific duties and in particular fire suppression, but the reasons for this increase in risk are not well understood. Exposure to wood smoke may alter blood vessel function and increase blood clot formation to explain the link between fire suppression and heart attacks.

The investigators wish to determine the effect of exposure to wood smoke at concentrations found at the perimeter of a woodland fire on blood vessel function and clotting in healthy non-smoking male professional firefighters or volunteers. Volunteers will be studied before and after inhalation of wood smoke or clean air for one hour in a purpose built whole-body exposure chamber. The investigators will perform comprehensive vascular assessments thereafter.

Understanding the effects of wood smoke on the blood vessels and clotting will be an important first step in helping to protect firefighters from heart disease. Through research, the investigators hope to identify methods to minimise the risk of heart attacks in firefighters and understand the health effects of a major source of air pollution that is relevant to the general population.

• Procedure: Forearm Vascular Study
  Forearm venous occlusion plethysmography to measure forearm blood flow during intra-arterial infusion of the vasodilators Verapamil (10-100 µg/min), bradykinin (100-1000 pmol/min), sodium nitroprusside (2-8 µg/min) and Acetylcholine (5-20 µg/min).
  Other Names:

  • Other Names:
  • BK
  • SNP
  • ACh
• Procedure: Badimon Chamber
  Ex-vivo assessment of thrombus formation using the Badimon Chamber

• Sham Comparator: Filtered Air Exposure
  1 hour exposure to filtered air during intermittent exercise
  Interventions:

  • Procedure: Forearm Vascular Study
  • Procedure: Badimon Chamber
• Active Comparator: Woodsmoke Exposure
  1 hour exposure to dilute woodsmoke at a concentration of 1000µg/m3 during intermittent exercise
  Interventions:

  • Procedure: Forearm Vascular Study
  • Procedure: Badimon Chamber

Inclusion Criteria:

• Non-smoking healthy male firefighters or volunteers

Exclusion Criteria:

• Current smoker or regular users of snus
• History of lung or ischaemic heart disease
• Malignant arrhythmia
• Systolic blood pressure >190mmHg or <100mmHg
• Renal or hepatic dysfunction
• Previous history of blood dyscrasia
• Unable to tolerate the supine position
• Blood donation within the last 3 months
• Recent respiratory tract infection within the past 4 weeks
• Routine medication including aspirin and NSAIDs

• Umeå University
• NHS Lothian