Ribonucleic Acid Hydrolysis by Intestinal Explants of Neonatal Piglets

Abstract

Background: Healthy human adults are able to hydrolyze dietary nucleic acids and nucleotides in the gastrointestinal tract, thus facilitating absorption of the resulting nucleosides. However, little is directly known of the ability of infants to hydrolyze nucleic acids early in life. Methods: Purified RNA (50, 100, 250, and 500 mg/L) in a suitable medium was exposed to jejunal explants of weaning piglets to determine if enzymes expressed by the explants were sufficient to hydrolyze the nucleic acid. Aliquots from the media were taken at time intervals, from 0 to 6 hours, and assayed for ribonucleoside content by high-performance liquid chromatography. Results: The investigators found a significant increase of free ribonucleosides during the study period and for all RNA concentrations tested, thus suggesting that intestinal explants are able to hydrolyze RNA. The kinetics of nucleoside concentrations varied for each nucleoside. For example, inosine increased over the entire 6-hour period and adenosine increased for the first 2 hours, decreasing afterward. Conclusions: It is concluded that cells from the intestinal epithelium are capable of hydrolyzing RNA. These results suggest that RNA present in human milk is hydrolyzed in the intestinal tract of the breast-fed infant, thus providing an additional source of nucleosides. The results indicate that current supplementation of infant formulas with nucleotides should be reconsidered to take into account the contribution of RNA present in human milk to the pool of bioavailable nucleotides. JPGN 35:685-690, 2002.

Exogenous nucleic acids and nucleotides are efficiently hydrolysed and taken up as nucleosides by intestinal explants from suckling piglets

“…Since the piglet intestinal explants were washed before culture, it appears the hydrolysis of RNA can be achieved in the absence of pancreatic ribonuclease and that enterocyte phosphodiesterase should be the main enzyme responsible for the hydrolysis. The present result confirms previous findings reported by our group (Rueda et al 2002). In addition, Kuchan et al (2000) studied the influence of purine intake on uric acid excretion in infants fed on soya infant formulas suggesting that healthy infants can digest RNA and subsequently absorb the ribonucleotides liberated.…”

“…The efficiency of these enzymes to catabolize RNA and NT to absorbable products on a quantitative basis needs to be further investigated. A previous study from our group showed that cells from the intestinal epithelium are capable of hydrolysing RNA (Rueda et al 2002).…”

Effect of Dietary Ribonucleotides on Infant Immune Status. Part 1: Humoral Responses

“…Ribonucleotides appear to play an important role in intestinal physiology. Dietary ribonucleotides are rapidly catabolized (39) in the intestinal epithelium (40,41), are efficiently absorbed into enterocytes as nucleosides and free bases (42), and were also shown to have discernible effects on intestinal vascular blood flow (43). Immune response to OPV primarily linked with efficient functioning of gut-associated immune cell populations may have been influenced by the presence of dietary ribonucleotides.…”

Development of a 3D printed device to support long term intestinal culture as an alternative to hyperoxic chamber methods

“…Although explants were only kept viable for a maximum of 24 h in this experiment, this period is suitable for the majority of studies focused at pathogen-host interactions [ 8 – 10 ]. In addition, the ability to manipulate the gas media that explants are exposed can benefit studies aimed at intestinal physiology [ 11 ] and nutrition [ 12 ] by simulating more closely the luminal gas environment normally observed in vivo. Although providing continual circulation, this setup uses considerably more culture media compared to a 6-well culture plate setup (3 mL vs 100 mL) to continuously provide explants with nutrients and with metabolite clearance by dilution.…”