Background: Meconium has the potential for being the matrix on which markers of fetal exposure to physiologic and non-physiologic agents during intrauterine life can be analyzed. The aim of this study was to compare trypsin and antitrypsin activities and protein concentration during intra- and extrauterine human development based on an assessment of these parameters in serial meconium and first feces of healthy, term newborns during the first four days of life.
Methods: One hundred and eighteen mature, term newborns were studied. Single portions of meconium or feces were taken prospectively from day 1 to day 4. In ten newborns each meconium and feces passed by the infant from birth up to the fourth day after delivery was collected individually. Trypsin activity was measured using L-TAPA (N-alpha-tosyl-l-arginine-p-nitroanilide) as substrate, trypsin inhibitory capacity (TIC) with N-alpha-benzoyl-dl-arginine-p-nitroanilide (BAPNA) as substrate, and protein concentration by the method of Lowry et al.
Results: Meconium and feces of healthy newborns demonstrated a decrease in TIC during the first two days of life and an increase in trypsin activity over the first three successive days of life. No correlation was observed between the variability of both parameters. During the first three days of a newborn's life, significant correlation was observed between TIC and protein concentration in meconium and first feces. In the course of proteolytic activity changes in successive portions of meconium and feces, a transient peak occurs on the 2nd-4th day of life.
Conclusions: The gradual decrease in protease inhibitor activity and low trypsin activity in successive portions of meconium from the first two days of extrauterine life may provide a retrograde chronological depiction of the course of the second and third trimesters of intrauterine life. Serial collection of feces over 2-4 days may provide a reflection of the dynamics of the postnatal increase in the newborn's pancreatic exocrine functions.