Urinary leukotriene E4 levels increase upon exposure to hypobaric hypoxia

Area of Science:

• Environmental Physiology
• Biochemistry
• Altitude Medicine

Background:

• Acute mountain sickness (AMS) is a common condition affecting individuals ascending to high altitudes.
• The pathophysiological mechanisms underlying AMS are not fully understood.
• Leukotrienes are inflammatory mediators that may play a role in altitude-induced physiological changes.

Purpose of the Study:

• To investigate if urinary leukotriene E4 (uLTE4) levels rise with high-altitude exposure.
• To explore the correlation between uLTE4 levels and the severity of AMS symptoms.
• To assess the potential involvement of leukotrienes in AMS.

Main Methods:

• A prospective, unblinded experimental study was conducted at sea level, moderate altitude (1,830 m), and high altitude (4,300 m).
• Eight healthy young male subjects participated.
• Urinary leukotriene E4 (uLTE4) levels were measured, alongside AMS symptoms assessed via the Environmental Symptoms Questionnaire, and oxygen saturation via pulse oximetry.

Main Results:

• Mean uLTE4 levels showed a statistically significant increase at high altitude (134.8 pg/mg creatinine) compared to sea level (67.9 pg/mg creatinine) and moderate altitude (82.3 pg/mg creatinine).
• The increase in uLTE4 occurred shortly after ascent to high altitude, even after acclimatization at moderate altitude.
• A clear relationship between uLTE4 levels and AMS symptom severity was not established in this study.

Conclusions:

• Urinary leukotriene E4 (uLTE4) levels increase upon exposure to high altitude.
• The findings support the hypothesis that leukotrienes are involved in the pathophysiology of acute mountain sickness (AMS).
• Further research is needed to elucidate the precise relationship between uLTE4 and AMS symptoms.