Urinary desmosine, elastolysis, and lung disease.

Area of Science:

• Biochemistry
• Physiology
• Medical Research

Background:

• Desmosine is a unique amino acid found in elastin.
• Urinary desmosine (UD) is proposed as a marker for endogenous elastin degradation.
• Previous studies found no elevation of UD in chronic obstructive airways disease (COAD), despite its suspected role in the condition.

Purpose of the Study:

• To investigate day-to-day and between-subject variability in urinary desmosine.
• To determine the contribution of dietary desmosine to urinary levels in humans.
• To assess the utility of UD as a marker for elastolysis in COAD.

Main Methods:

• Collected 24-hour urine samples over 5 consecutive days from 10 asymptomatic subjects.
• Measured urinary desmosine and creatinine levels.
• Administered radiolabeled desmosine and elastin to assess dietary contribution.
• Compared UD excretion on normal and low-elastin diets.

Main Results:

• Mean 24-hour UD output was significantly higher in males than females.
• Gender-specific analysis minimized between-subject variation in UD.
• Dietary desmosine accounted for approximately 15% of urinary desmosine on a normal diet.
• Reducing dietary desmosine intake lowered within-subject variation but did not affect between-subject variation or overall UD levels.

Conclusions:

• Urinary desmosine excretion exhibits considerable variability, influenced by gender.
• Dietary intake has a modest impact on urinary desmosine levels.
• Further research is needed to understand the factors contributing to UD variability and its role in diseases like COAD.