Comparison of protease and aminopeptidase activities in meconium: A pilot study

Ewa Skarżyńska; Paulina Wilczyńska; Bartosz Kiersztyn; Joanna Żytyńska-Daniluk; Artur Jakimiuk; Barbara Lisowska-Myjak

doi:10.3892/br.2020.1314

Comparison of protease and aminopeptidase activities in meconium: A pilot study

Biomed Rep. 2020 Aug;13(2):7. doi: 10.3892/br.2020.1314. Epub 2020 Jun 9.

Authors

Ewa Skarżyńska¹, Paulina Wilczyńska², Bartosz Kiersztyn³, Joanna Żytyńska-Daniluk⁴, Artur Jakimiuk⁵, Barbara Lisowska-Myjak¹

Affiliations

¹ Department of Biochemistry and Clinical Chemistry, Medical University of Warsaw, Warsaw 02-097, Poland.
² Department of Biochemistry, Warsaw University of Life Sciences - SGGW, Warsaw 02-776, Poland.
³ Microbial Ecology and Environmental Biotechnology Department, Institute of Botany, Faculty of Biology, University of Warsaw; Biological and Chemical Research Centre, Warsaw 02-089, Poland.
⁴ Clinical Department of Obstetrics, Female Diseases and Gynaecological Oncology, Central Clinical Hospital of The Ministry of The Interior, Warsaw 02-507, Poland.
⁵ Reproductive Health Department, Institute of Mother and Child, Warsaw 01-211, Poland.

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.

Keywords: activity; aminopeptidases; cesarean; meconium; parturition; proteases; vaginal birth.