A New Murine Undernutrition Model Based on Complementary Feeding of Undernourished Children Causes Damage to the Morphofunctional Intestinal Epithelium Barrier.

BACKGROUND: Complementary feeding is critical in establishing undernutrition. However, experimental undernourished diets do not represent the amount of nutrients in the complementary diets of undernourished children. OBJECTIVES: To develop, validate, and evaluate the impact of a new murine model of undernutrition on the intestinal epithelium, based on the complementary diet of undernourished children from 7 countries with low-socioeconomic power belonging to the Malnutrition-Enteric Diseases (MAL-ED) cohort study. METHODS: We used the difference in the percentage of energy, macronutrients, fiber and zinc in the complementary diet of children without undernutrition compared with stunting (height-for-age Z-score < -2) for the MAL-ED diet formulation. Subsequently, C57BL/6 mice were fed a control diet (AIN-93M diet) or MAL-ED diet for 28 d. Weight was measured daily; body composition was measured every 7 d; lactulose:mannitol ratio (LM) and morphometry were evaluated on days 7 and 28; the cotransport test and analysis of intestinal transporters and tight junctions were performed on day 7. RESULTS: The MAL-ED diet presented -8.03% energy, -37.46% protein, -24.20% lipid, -10.83% zinc, +5.93% carbohydrate, and +45.17% fiber compared with the control diet. This diet rapidly reduced weight gain and compromised body growth and energy reserves during the chronic period (P < 0.05). In the intestinal epithelial barrier, this diet caused an increase in the LM (P < 0.001) and reduced (P < 0.001) the villous area associated with an increase in FAT/CD36 in the acute period and increased (P < 0.001) mannitol excretion in the chronic period. CONCLUSIONS: The MAL-ED diet induced undernutrition in mice, resulting in acute damage to the integrity of the intestinal epithelial barrier and a subsequent increase in the intestinal area during the chronic period. This study introduces the first murine model of undernutrition for the complementary feeding phase, based on data from undernourished children in 7 different countries.

Use of antibiotics in children younger than two years in eight countries: a prospective cohort study.

OBJECTIVE: To describe the frequency and factors associated with antibiotic use in early childhood, and estimate the proportion of diarrhoea and respiratory illnesses episodes treated with antibiotics. METHODS: Between 2009 and 2014, we followed 2134 children from eight sites in Bangladesh, Brazil, India, Nepal, Pakistan, Peru, South Africa and the United Republic of Tanzania, enrolled in the MAL-ED birth cohort study. We documented all antibiotic use from mothers' reports at twice-weekly visits over the children's first two years of life. We estimated the incidence of antibiotic use and the associations of antibiotic use with child and household characteristics. We described treatment patterns for diarrhoea and respiratory illnesses, and identified factors associated with treatment and antibiotic class. FINDINGS: Over 1 346 388 total days of observation, 16 913 courses of antibiotics were recorded (an incidence of 4.9 courses per child per year), with the highest use in South Asia. Antibiotic treatment was given for 375/499 (75.2%) episodes of bloody diarrhoea and for 4274/9661 (44.2%) episodes of diarrhoea without bloody stools. Antibiotics were used in 2384/3943 (60.5%) episodes of fieldworker-confirmed acute lower respiratory tract illness as well as in 6608/16742 (39.5%) episodes of upper respiratory illness. Penicillins were used most frequently for respiratory illness, while antibiotic classes for diarrhoea treatment varied within and between sites. CONCLUSION: Repeated antibiotic exposure was common early in life, and treatment of non-bloody diarrhoea and non-specific respiratory illnesses was not consistent with international recommendations. Rational antibiotic use programmes may have the most impact in South Asia, where antibiotic use was highest.

Prevalence and virulence gene profiling of enteroaggregative Escherichia coli in malnourished and nourished Brazilian children.

The impact of enteroaggregative E. coli (EAEC) infection on childhood malnutrition and inflammation has been suggested, regardless of diarrhea. We investigated whether EAEC and its virulence-related genes (VRGs) are associated with malnutrition in a case-control study. Children aged 6-24 months from Brazil were enrolled as malnourished if weight-for-age Z-score (WAZ) ≤ -2 and nourished if WAZ > -1. Stools were cultured and examined for E. coli. DNA was extracted from fecal isolates and tested for EAEC by polymerase chain reaction (PCR). Positive samples were analyzed by 5 multiplex PCRs to identify 20 EAEC VRGs. Biomarkers of intestinal barrier function and inflammation were measured. The prevalence of EAEC was 39.94%. Samples that presented both aaiC and aatA genes were associated with malnutrition (P = 0.045). A high prevalence of VRGs was observed and the aafC gene was significantly associated with malnourished (P = 0.0101). Strains lacking aar and pic genes were associated with malnutrition (P = 0.018), while the concomitant presence of aar, pic, agg4A, and capU genes was associated with nourished (P = 0.031). These data reinforce the EAEC impact on malnutrition, the importance of aar as negative regulator and the great contribution of AAF/II fimbria for the pathobiology of EAEC.

Effects of glutamine alone or in combination with zinc and vitamin A on growth, intestinal barrier function, stress and satiety-related hormones in Brazilian shantytown children

OBJECTIVE: To determine the impact of supplemental zinc, vitamin A, and glutamine alone or in combination on growth, intestinal barrier function, stress and satiety-related hormones among Brazilian shantytown children with low median height-for-age z-scores. METHODS: A randomized, double-blind, placebo-controlled trial was conducted in children aged two months to nine years from the urban shanty compound community of Fortaleza, Brazil. Demographic and anthropometric information was assessed. The random treatment groups available for testing (a total of 120 children) were as follows: (1) glutamine alone, n = 38; (2) glutamine plus vitamin A plus zinc, n = 37; and a placebo (zinc plus vitamin A vehicle) plus glycine (isonitrogenous to glutamine) control treatment, n = 38. Leptin, adiponectin, insulin-like growth factor (IGF-1), and plasma levels of cortisol were measured with immune-enzymatic assays; urinary lactulose/mannitol and serum amino acids were measured with high-performance liquid chromatography. ClinicalTrials.gov: NCT00133406. RESULTS: Glutamine treatment significantly improved weight-for-height z-scores compared to the placebo-glycine control treatment. Either glutamine alone or all nutrients combined prevented disruption of the intestinal barrier function, as measured by the percentage of lactulose urinary excretion and the lactulose:mannitol absorption ratio. Plasma leptin was negatively correlated with plasma glutamine (p = 0.002) and arginine (p = 0.001) levels at baseline. After glutamine treatment, leptin was correlated with weight-for-age (WAZ) and weight-for-height z-scores (WHZ) (p≤0.002) at a 4-month follow-up. In addition, glutamine and all combined nutrients (glutamine, vitamin A, and zinc) improved the intestinal barrier function in these children. CONCLUSION: Taken together, these findings reveal the benefits of glutamine alone or in combination ...

Glutamine Analogues As Adjunctive Therapy for Infectious Diarrhea.

Glutamine is the major fuel for the gut as well as for many cells in the immune system that becomes conditionally essential during catabolic states. Glutamine supplementation improves intestinal mucosal repair and function. Glutamine, even at high doses, is without side effects and is well tolerated. Though unstable in solution, this is overcome by creating stable dipeptides such as alanyl-glutamine. In HIV-positive patients with wasting, glutamine enhances intestinal absorptive function and weight gain. Glutamine enhances sodium and water absorption in a rabbit model of cholera and Cryptosporidium-infected piglet intestine. Both glutamine and alanyl-glutamine have recently proven effective in a bovine model of Cryptosporidium as well. Finally, a rat model of cholera toxin-induced diarrhea also showed that alanyl-glutamine enhanced water and electrolyte intestinal absorption even better than the traditional glucose solutions. Clearly glutamine and its stabler derivatives hold promise for enhancing repair of mucosal injury by a wide range of infections or toxic agents, and hence have great potential as a new oral rehydration and nutrition therapy for patients with enteric infection, malnutrition, or chemotherapy- or radiation-induced enteritis.