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Dietary nucleotides may influence the humoral immunity in immunocompromised children

1997; Elsevier BV; Volume: 13; Issue: 5 Linguagem: Inglês

10.1016/s0899-9007(97)00012-9

1873-1244

Olga Martínez‐Augustin, J. Bozá, Joaíquin Navarro, Antonio Martínez‐Valverde, Magdalena Araya, Ángel Gil,

Adenosine and Purinergic Signaling

Dietary nucleotides ( NTs) are considered nonessential nutrients, but under certain conditions may behave as semi-essential. This means that they may become essential when the exogenous supply is insufficient for normal function, even though their absence from the diet does not lead to a classic clinical deficiency syndrome.’ Recent studies have examined the effects of dietary NTs on the gut, showing that they may be important in achieving optimal gut development and growth, especially after intestinal injury.‘mh In addition, there is evidence of the potential role of exogenous NTs as modulators of the immune function.7m’4 In recent years we have carried out a series of studies in order to determine the influence of dietary NT supplementation on the intestinal absorption of macromolecules, intestinal permeability, serum immunoglobulin (Ig) levels, and the development of circulating antibodies against /?-lactoglobulin and (Ycasein in preterm infants for the first month of life. Moreover, additional studies have been carried out to determine their influence on the recovery of malnourished and infected children with diarrhea. Twenty-seven preterm infants born between 32 and 36 wk of gestational age (which was estimated according to the mother’s last period), weighing between 1500 and 2200 g were enrolled in the present study upon admission to the Hospital Matemo Infantil of Malaga, Spain. All infants were free from major neonatal disease and were able to tolerate enteral feeding within 48 h after birth. Infants were assessed at 1, 7, and 30 d of age, when blood and urine samples were obtained after the administration of a dose of lactulose and mannitol (300 and 60 mg, respectively) dissolved in the liquid diet. Eleven infants were fed a standard low-birth-weight infant formula (F) and 16 infants were fed the same formula supplemented with NTs (FN) for 30 d.* Lactulose and mannitol in urine were determined by gasliquid chromatography following the method previously described by Martinez-Augustin et ~1.‘~ and P-lactoglobulin serum concentration was measured by a modification of the ELISA method described by Husby et ul. I6 There were no significant differences between the lactulose/ mannitol ratios in the urine of children fed F or FN at any of the timepoints considered in the study. While the lactulose/ mannitol ratio was the same or slightly higher in infants fed FN during the first week of life, this ratio decreased significantly at 30 d of life in both groups (Fig. 1). Intact P-lactoglobulin was detected in the serum of all infants included in the study at 1,7, and 30 d of life. Nevertheless, there were no significant differences either timewise or between the formulas used (Fig. 1) . Thus, in this study we could confirm the presence of enhanced intestinal permeability in preterm infants during the first week of life, whereas gut closure was effective at 30 d of life. Although it has been shown that dietary NTs have relevant effects on the intestinal growth and rate of maturation in young rats as assessed by mucosal weight, RNA and DNA content, protein concentrations, and activity of brush border enzymes,4 our data showed that NT supplementation of the low-birthweight infant formula did not lead to any change in the intestinal permeability in the preterm infant.