Serum PAF acetylhydrolase increases during neonatal maturation.

Area of Science:

• Biochemistry
• Immunology
• Neonatology

Background:

• Platelet-activating factor (PAF) is a potent inflammatory mediator.
• Acetylhydrolase degrades PAF to its inactive form, lysoPAF, playing a key role in PAF regulation.
• Low acetylhydrolase activity may increase susceptibility to PAF-related neonatal diseases like necrotizing enterocolitis.

Purpose of the Study:

• To investigate the effect of age on serum acetylhydrolase activity in human subjects.
• To determine if acetylhydrolase activity differs between newborns and older individuals.
• To assess the developmental trajectory of acetylhydrolase activity in early life.

Main Methods:

• Serum samples were collected from 70 subjects aged 4 hours to 48 years.
• Acetylhydrolase activity was measured using radio-labelled PAF and quantifying reaction products.
• Statistical analysis was performed to compare activity across different age groups and correlate it with age.

Main Results:

• Serum acetylhydrolase activity was significantly lower in newborns (less than 3 weeks) compared to all other age groups (8.2 nmole/ml/min vs 30.0 nmole/ml/min).
• Enzyme activity showed a linear increase with the natural logarithm of age from birth to 6 weeks (r=0.65, p<0.001).
• Newborn acetylhydrolase activity was comparable between term and preterm infants.

Conclusions:

• Human neonatal serum acetylhydrolase activity is markedly low.
• Activity increases substantially during the first six weeks of life, approaching adult levels.
• Neonates may have an elevated risk for pathophysiological conditions mediated by PAF due to lower acetylhydrolase levels.