Racial differences in resting end-tidal CO2 and circulating sodium pump inhibitor

Area of Science:

• Cardiovascular Physiology
• Respiratory Medicine
• Human Physiology

Background:

• High end-tidal CO2 (PetCO2) is linked to sodium sensitivity of blood pressure (BP) in White Americans.
• African Americans exhibit greater BP sensitivity to high sodium intake compared to White Americans.

Purpose of the Study:

• To test the hypothesis that resting PetCO2 is higher in normotensive African Americans than in White Americans.
• To investigate the relationship between PetCO2, sodium balance, and BP in different racial groups.

Main Methods:

• Resting end-tidal CO2 (PetCO2) was monitored in 395 White and 125 African American participants.
• Blood pressure (BP) and heart rate were recorded periodically.
• Twenty-four-hour urinary excretion of marinobufagenin-like compound (MBG) was analyzed.

Main Results:

• Mean resting PetCO2 was significantly higher in African American men and women compared to White men and women, especially those over 50 years old.
• Urinary MBG excretion was higher in White participants than in African American participants.
• High PetCO2 independently predicted high MBG excretion in African Americans.

Conclusions:

• Higher resting PetCO2 in African Americans may contribute to slower sodium excretion and increased BP sensitivity to sodium.
• These findings support a role for PetCO2 in the higher prevalence of hypertension in African Americans.
• PetCO2 emerges as a potential biomarker for sodium sensitivity and hypertension risk across racial groups.