Impact of Different Strategies for Delivering Supplemental Zinc on Selected Fecal Markers of Environmental Enteric Dysfunction among Young Laotian Children: A Randomized Controlled Trial

Stool biomarkers as measures of enteric pathogen infection in infants from Addis Ababa informal settlements

Frequent enteric infections in children may be an important cause of growth faltering; however, we do not fully understand the mechanisms by which pathogen infections and the physiological responses to these infections result in poorer growth. Commonly used protein fecal biomarkers (anti-alpha trypsin, neopterin, and myeloperoxidase) provide broad immunological information on an inflammatory response; however, they do not provide information on non-immune processes (e.g., gut integrity) that may be important indicators of chronic end states such as environmental enteric dysfunction (EED). To explore how additional biomarkers will better inform which physiological pathways (both immune and non-immune) are impacted by pathogen exposure we added to the traditional panel of 3 protein fecal biomarkers 4 novel fecal mRNA transcript biomarkers (sucrase isomaltase, caudal homeobox 1, S100A8, and mucin 12) and analyzed stool samples from infants living in informal settlements in Addis Ababa, Ethiopia. To test how this expanded biomarker panel captures distinct pathogen exposure processes we used two different scoring systems. First, we used a theory-based approach to assign each biomarker to specific physiological attributes based on prior understanding of each biomarker. Second, we used data reduction methods to categorize biomarkers and then assign physiological attributes to those categories. We used linear models to examine the association between the derived biomarker scores (based on mRNA and protein levels) and stool pathogen gene counts to determine pathogen specific effects on gut physiology and immune responses. Inflammation scores were positively associated with Shigella and enteropathogenic E.Coli (EPEC) infection, while gut integrity scores were negatively associated with Shigella, EPEC and, shigatoxigenic E.coli (STEC) infection. Our expanded panel of biomarkers hold promise as tools to measure systemic outcomes of enteric pathogen infection. mRNA biomarkers complement established protein biomarkers by providing important cell-specific physiological and immunological consequences of pathogen carriage that can lead to chronic end states such as EED.

Daily preventive zinc supplementation increases the antibody response against pathogenic Escherichia coli in children with zinc insufficiency: a randomised controlled trial

Zinc deficiency impairs the antibody-mediated immune response and is common in children from lower-income countries. This study aimed to investigate the impact of different zinc supplementation regimens (7, 10 or 20 mg/day elemental zinc)—therapeutic dispersible zinc tablets (TZ), daily multiple micronutrient powder (MNP), daily preventive zinc tablets (PZ) and placebo powder (control)—and compare between baseline and endline antibody production against pathogenic Escherichia coli in Laotian children (aged 6–23 months). Fifty representative plasma samples of each treatment group were randomly selected from 512 children to determine anti-E. coli IgG antibody levels and avidity. Of the 200 children, 78.5% had zinc deficiency (plasma zinc concentration < 65 µg/dL) and 40% had anaemia before receiving zinc supplementation. aAfter receiving the TZ, MNP or PZ regimen, the plasma anti-E. coli IgG levels were significantly increased compared with baseline; the effect on the antibody level was more pronounced in children with zinc deficiency. Interestingly, there was increased anti-E. coli IgG avidity in the control and PZ groups. This study suggests that PZ might be the optimal zinc supplementation regimen to increase both the quantity and quality of antibody responses in children with zinc deficiency. Clinical trial registration: https://clinicaltrials.gov/ct2/show/NCT02428647 (NCT02428647, 29/04/2015).