Increased sweat sulfate concentrations in chronic renal failure

Area of Science:

• Nephrology
• Dermatology
• Biochemistry

Background:

• Inorganic sulfate is significantly elevated in patients with chronic renal failure (CRF).
• Hemodialysis effectively reduces circulating sulfate levels in CRF patients, while chloride levels remain stable.
• Understanding sulfate handling in CRF is crucial for managing dialysis-related complications.

Purpose of the Study:

• To investigate inorganic sulfate and chloride concentrations in sweat of CRF patients.
• To compare sweat sulfate excretion with serum sulfate levels before and after hemodialysis.
• To explore the relationship between sweat composition and dialysis-related pruritus.

Main Methods:

• Pilocarpine iontophoresis was used to collect sweat samples from CRF patients and healthy controls.
• Sulfate and chloride concentrations in sweat and serum were measured.
• Fractional excretion of sulfate and chloride in sweat was calculated.

Main Results:

• Sweat sulfate concentrations were significantly higher in CRF patients compared to controls (404 +/- 43 vs. 105 +/- 6 microM).
• A significant positive correlation was observed between plasma and sweat sulfate concentrations in CRF patients (r = 0.77).
• The fractional excretion of sulfate in sweat remained consistent before and after dialysis, similar to chloride, despite major changes in serum sulfate levels.

Conclusions:

• Sweat glands handle inorganic sulfate similarly to chloride in CRF patients.
• Hemodialysis substantially reduces absolute sulfate excretion via sweat.
• Reduced sulfate excretion post-hemodialysis may decrease calcium sulfate complex formation, potentially alleviating skin pruritus in CRF patients.