Thermal sweat lactate in cystic fibrosis and in normal children

Area of Science:

• Physiology
• Biochemistry
• Sweat Gland Function

Background:

• Cystic fibrosis (CF) is characterized by abnormal ion transport, affecting sweat composition.
• Previous research indicates altered sodium (Na+) and potassium (K+) handling in CF sweat.
• The metabolic state of CF sweat glands remains incompletely understood.

Purpose of the Study:

• To investigate the association between altered sweat electrolyte excretion and anaerobic metabolism in CF.
• To evaluate sweat lactate excretion rate as an indicator of glandular energy metabolism in CF patients.

Main Methods:

• Forehead sweat was collected from 6 children with CF and 11 healthy children under thermal load (45°C).
• Sweat electrolyte concentrations (Na+, K+, Cl-) and lactate excretion rates were measured.
• Excretion rates were analyzed in relation to sweat flow rate (Qsw).

Main Results:

• In CF patients, Na+, K+, and Cl- concentrations remained constant across varying sweat flow rates.
• Sweat electrolyte excretion rates increased linearly with sweat flow rate in both CF and control groups.
• The slopes for electrolyte excretion were significantly steeper in CF patients compared to controls (p < 0.001).
• Sweat lactate excretion rate increased with sweat flow rate similarly in both CF and control groups.

Conclusions:

• CF sweat glands exhibit normal anaerobic metabolism, as indicated by consistent sweat lactate excretion rates.
• Increased energy expenditure for Na+-K+ exchange and active K+ secretion may explain the observed metabolic profile in CF.
• These findings suggest that CF sweat glands can maintain energy homeostasis despite ion transport abnormalities.