Maturation status of small intestine epithelium in rats deprived of dietary nucleotides

Abstract

SummarvWe describe the changes of several brush-border enzymatic activities in different subpopulations of epithelial cells, separated sequentially from the villus tip-to-crypt axis of the small intestine, induced by deprivation of dietary nucleotides for different periods of time in adult rats. Deprivation of dietary nucleotides lead to a decrease in the content and specific activity of alkaline phosphatase, leucineaminopeptidase, maltase, sucrase and lactase in the villus tip, but had little effect on the crypt zone. The effect of the nucleotide deprivation on the enzymatic activity progressively increased towards the tip of the villus. Since these enzymes are maturation markers of the intestinal cells, these results support the idea that dietary nucleotides affect the maturation status of small-intestine epithelium.

The Role of Nucleotides in the Immune and Gastrointestinal Systems

“…Of the 2%−5% of dietary nucleotides incorporated into body pools and used for nucleic acid synthesis, 25%−50% are found in the GI tract 44 . Therefore, given the potential absence of the capability to synthesize purines and the inefficiency for synthesis of pyrimidines, exogenous sources of nucleotides may be necessary to meet the requirements of the GI tract 51 …”

Exogenous nucleosides modulate expression and activity of transcription factors in Caco-2 cells

“…Supplementation of diets with NTs or NSs is common in infant formulas and enteral nutrition because of their positive effects in conditions of rapid growth, such as the neonatal period and tissue repair after surgery or injury [2][3][4][5]. They serve as building blocks for RNA and DNA synthesis and have important effects on the growth and differentiation of cells, especially those with a rapid turnover, such as the immune system and the gastrointestinal tract [6][7][8][9][10][11]. Moreover, intestinal homeostasis may depend on exogenous supplies of NTs because the de novo NT synthesis seems to be limited.…”

Nucleotídeos na dieta de frangos de corte e seus efeitos sobre taxa de turnover da mucosa intestinal antes e após lesões causadas por coccidiose

“…Verifica-se que o valor-meia vida encontrado foi menor para os animais que receberam dieta suplementada, indicando que a suplementação com nucleotídeos propicia aceleração na velocidade de troca do carbono na mucosa intestinal de frangos de corte na fase inicial de crescimento e, portanto, maior aceleração no crescimento intestinal. Esses resultados corroboram os encontrados por outros autores, demonstrando que, ao suplementar a dieta de ratos com nucleotídeos, ocorre aceleração do desenvolvimento do intestino (TSUJINAKA et al, 1993) e aumento do conteúdo de DNA da mucosa intestinal (UAUY et al, 1990), suportando a teoria de que os nucleotídeos afetam positivamente o crescimento e maturação do epitélio do intestino delgado (ORTEGA et al, 1995).…”