Recovery of exfoliated cells from the gastrointestinal tract of premature infants: a new tool to perform "noninvasive biopsies?"

To gain insight into specific gene expression in the gastrointestinal (GI) tract of preterm infants, we adapted a method to isolate exfoliated epithelial cells. Gastric residual fluid aspirates (n = 89) or stool samples (n = 10) were collected from 96 neonates (gestational age, 24-36 wk). Cells were characterized by microscopic observation, cytokeratin-18 immunodetection, and expression of transcripts. The human origin of cellular DNA was confirmed by amplification of specific X and Y chromosome sequences. Isolation yielded 100-500 cells per sample for gastric aspirates (n = 8) and 10-20 cells for fecal samples (n = 5). Epithelial origin was confirmed by immunodetection of cytokeratin 18. Analyses of reverse transcribed products, using two independent methods, from 15 gastric fluid and two stool samples showed that 18S-rRNA and transcripts of beta-actin, glyceraldehyde-3-phosphate dehydrogenase (gapdh), and period1 were in quantities corresponding to at least 10 cells. On 59 aspirates, we found beta-actin transcripts (all but one), cytokeratin 18 (eight positive of eight samples), SLC26-A7-1 (13 positive of 19 samples), period2 (17 positive of 17 samples), and clock (25 positive of 26 samples). Exfoliated cells can be recovered from gastric aspirates and fecal samples and serve as a tool to investigate the impact of therapeutic and nutritional regimens on the maturation of GI functions.

Methods used to study intestinal nutrient transport: past and present

BACKGROUND

Vitally important to the future of surgical care is the study of nutrition and nutrient uptake. Advances in this field of research have become increasingly dependent upon the disciplines of immunology, histology, and molecular biology. The fusion of these sciences has deepened our insight into the relationship between molecular structure and physiologic function. The ability to apply new technologies to this endeavor will enable the surgeon-investigator to further widen our understanding of nutrient transport.

MATERIALS AND METHODS

Medline and current literature review.

RESULTS AND CONCLUSIONS

We summarize many of the methods used to measure the uptake of nutrients by the intestinal epithelium, providing a historical perspective.