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Comparison of protease and aminopeptidase activities in meconium: A pilot study
Ewa Skarżyńska1, Paulina Wilczyńska2, Bartosz Kiersztyn3
1Department of Biochemistry and Clinical Chemistry, Medical University of Warsaw, Warsaw 02-097, Poland.
Insights
Protease activity increases in infant meconium, while aminopeptidase activity remains stable. Vaginal birth correlates with more stable enzyme levels compared to cesarean section, suggesting a more consistent intrauterine environment.
Area of Science:
- Biochemistry
- Neonatal Physiology
- Developmental Biology
Background:
- Proteases and aminopeptidases are key physiological components in fetal development within the intrauterine environment.
- Meconium composition provides insights into fetal physiological processes.
Purpose of the Study:
- To assess changes in protease and aminopeptidase activity in healthy infant meconium.
- To investigate the association between enzyme activity and mode of delivery (vaginal vs. cesarean section).
Main Methods:
- Enzyme activities were measured in 110 meconium samples using specific substrates.
- Serial meconium samples were collected from neonates born vaginally (n=14) and via cesarean section (n=16).
Main Results:
- Protease activity significantly increased from the first to the last meconium sample (P=0.004).
- Aminopeptidase activity showed no significant change between consecutive samples (P=0.702).
- Enzyme activity ratios were lower for proteases than aminopeptidases and sustained in cesarean-born infants.
- Vaginally born infants showed a stronger correlation between early and late meconium enzyme activity compared to cesarean-born infants.
Conclusions:
- Aminopeptidase activity is stable during fetal intestinal meconium accumulation.
- Mode of delivery influences the stability of protease and aminopeptidase activity in meconium.
- Vaginal birth may be associated with a more stable intrauterine enzymatic environment compared to cesarean section.
Abstract:
The successive accumulation of proteases and aminopeptidases in meconium are important physiological components of the intrauterine environment in which a fetus develops. The aim of the present study was to assess the changes in the activities of these enzymes in meconium of healthy infants, and to investigate whether there were any statistically significant associations between activity of the enzymes of interest and the mode of delivery. The activities of proteases and aminopeptidases were determined in meconium portions (n=110) using the substrates BODIPY FL casein and L-leucine-7-amido-4-methylcoumarin hydrochloride, respectively. Serial meconium samples (2-5 per neonate) were collected from healthy infants born vaginally (n=14), and by a cesarean section (n=16). Protease activity (104 RFU/h) was lower in the first meconium sample compared with the final sample from the same infant (3.99±2.03 vs. 5.76±2.24, respectively, mean ± standard deviation; P=0.004). Conversely, there was no significant difference in aminopeptidase activity (103 nM/l/h) between consecutive meconium samples (P=0.702). The ratios of the first-meconium sample enzyme activity to the last-meconium sample enzyme activity were lower for proteases compared with aminopeptidases (0.76±0.48 vs. 1.35±1.04, respectively mean ± standard deviation; P=0.014), and sustained in the infants born by a cesarean section (P=0.008). Spearman's correlation coefficient analysis between the first and last meconium samples showed the correlation increased in the infants born vaginally compared with the rest of the infants (proteases, R=0.618 vs. R=0.314; aminopeptidases, R=0.688 vs. R=0.566). Aminopeptidase activity did not exhibit any notable dynamic changes during meconium accumulation in the fetal intestine. In infants born vaginally compared with those born by a cesarean section, the activity of both proteases and aminopeptidases in the first meconium sample showed an improved correlation with the activity of the final meconium sample. This may suggest that in the intrauterine environment, during accumulation of meconium in the digestive tract of the fetus, the activity and/or levels of these enzymes and the substrates they catalyze were more stable in newborns born vaginally compared with infants born by caesarean section.
