Search

Background Maternal influenza vaccination has been demonstrated to reduce influenza infections in infants. Influenza infections generally peak during the winter season, and several studies support the association between low levels of vitamin D during winter months and an increase in respiratory infections, including influenza. We examined the effects of vitamin D and maternal influenza vaccination status on laboratory confirmed influenza infections in infants less than 6 months of age. Methods Pregnant Bangladeshi mothers were randomized to receive influenza vaccine or pneumococcal vaccine as part of the Mother’s Gift study. Mothers reported breastfeeding frequency, along with episodes of infant respiratory illness with fever, every week for the first 6 months of life. If a respiratory illness with fever was reported, nasal swabs were obtained from the infant and tested with a commercial rapid influenza test. Infants with confirmed influenza disease were matched with four controls by birth month and sex, for a total of 84 controls. We measured 25-hydroxyvitamin D levels from cord blood in all cases and controls. A conditional logistic regression was performed to test the effect of vitamin D on the odds of laboratory confirmed influenza while controlling for birth weight, gestational age, crowding, number of siblings, and socioeconomic status score. Results A total of 21 infants had laboratory confirmed influenza disease. There were no significant differences in birth weight, crowding, family size, gestational age, socioeconomic status score, infant gender, and smokers in the home between cases and controls (Table 1). Frequency of maternal influenza vaccine was lower in cases when compared with controls (23.81% vs. 58.33%). Serum vitamin D was lower in cases than in controls (8.73 ± 3.34 vs. 10.67 ± 4.08, Table 2). Conclusion Both vitamin D levels and maternal vaccination status have medically relevant, and statistically significant, independent effects on the odds of infants contracting influenza. Although the vitamin D levels in the infants at birth were low, there was a significant association of lower levels at birth with an increased risk of influenza virus infection. Further study with a larger sample-size is needed to explore these effects. Disclosures All authors: No reported disclosures.

l-Glutamine (Gln) is a key metabolic fuel for intestinal epithelial cell proliferation and survival and may be conditionally essential for gut homeostasis during catabolic states. We show that l-alanyl-l-glutamine (Ala-Gln), a stable Gln dipeptide, protects mice against jejunal crypt depletion in the setting of dietary protein and fat deficiency. Separately, we show that murine crypt cultures (enteroids) derived from the jejunum require Gln or Ala-Gln for maximal expansion. Once expanded, enteroids deprived of Gln display a gradual atrophy of cryptlike domains, with decreased epithelial proliferation, but stable proportions of Paneth and goblet cell differentiation, at 24 h. Replenishment of enteroid medium with Gln selectively activates mammalian target of rapamycin (mTOR) signaling pathways, rescues proliferation, and promotes crypt regeneration. Gln deprivation beyond 48 h leads to destabilization of enteroids but persistence of EGFP- Lgr5-positive intestinal stem cells with the capacity to regenerate enteroids upon Gln rescue. Collectively, these findings indicate that Gln deprivation induces a reversible quiescence of intestinal stem cells and provides new insights into nutritional regulation of intestinal epithelial homeostasis.