Influence of barometric pressure on interleukin-1 beta secretion

Area of Science:

• Immunology
• Environmental Physiology
• Altitude Medicine

Background:

• Monocytes and macrophages are crucial immune cells responding to environmental stressors.
• These cells release cytokines like interleukin-1 beta (IL-1 beta) to manage physiological stress.
• The role of IL-1 beta in adapting to high-altitude environments requires further investigation.

Purpose of the Study:

• To test the hypothesis that high altitude stimulates IL-1 beta secretion from human blood mononuclear cells.
• To differentiate between pressure- and oxygen-related effects on IL-1 beta secretion at simulated high altitude.
• To understand immune cell adaptation to environmental challenges.

Main Methods:

• Isolated human blood mononuclear cells from six young men were cultured under various conditions: standard, hypobaric hypoxia, hypobaric normoxia, and normobaric hypoxia.
• Simulated altitude of 20,000 ft (6,096 m) was used, with controlled oxygen levels and pressure.
• Interleukin-1 beta (IL-1 beta) secretion was measured in both basal and lipopolysaccharide-stimulated cell cultures.

Main Results:

• Contrary to the hypothesis, basal IL-1 beta secretion was not induced by simulated high altitude.
• Lipopolysaccharide-stimulated IL-1 beta secretion was inhibited by approximately 40% under simulated altitude conditions.
• The inhibition of IL-1 beta secretion was attributed to reduced atmospheric pressure, not decreased oxygen levels (P = 0.039).
• Secretion of IL-1 receptor antagonist and soluble IL-1 receptor type II remained unaffected.

Conclusions:

• High altitude, specifically reduced pressure, inhibits IL-1 beta secretion from stimulated human immune cells.
• These findings challenge the initial hypothesis but offer insights into hematopoiesis and immune responses at altitude.
• Provides a cellular basis for historical practices of using high-altitude environments for health.