Giraffe
Member
- Joined
- Jun 20, 2015
- Messages
- 3,730
Vitamin A supplementation effects on intestinal barrier function, growth, total parasitic and specific Giardia spp. infections in Brazilian children: a prospective randomized, double-blind, placebo-controlled trial
"This study evaluates the effects of retinol on intestinal barrier function, growth, total parasites and Giardia spp. infections in children in the Northeast of Brazil." To increase the enrollment of children with marginally low levels of retinol and more prone to malnutrition, only children that had not exclusively been breast-fed were selected.
Children were treated with retinyl palmitate (100,000 IU for children <12 months and 200,000 IU for children at least 12 months old). The placebo group received 40 IU tocopherol. The children received the first supplementation at enrollment, a second dose after 4 months, and a final dose at 8 month.
Conclusions
"These data showed that total parasitic infection and Giardia spp. infections were significantly lower in the vitamin A treatment group when compared to the placebo group, suggesting that vitamin A improves host defenses against Giardia infections."
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The second study examines possible mechanism:
The retinoic acid-producing capacity of gut dendritic cells and macrophages is reduced during persistent T. muris infection.
Abstract
"Trichuris muris is an intestinal nematode that invades the colonic epithelium triggering a mucosal inflammation. Vitamin A and its active metabolite retinoic acid are strongly linked with the modulation of gut immune responses. Here, we describe the temporal changes in the expression of aldehyde dehydrogenase (ALDH) enzymes, responsible for converting dietary-absorbed vitamin A into the immuno-modulatory retinoic acid in lamina propria leucocytes post-infection. We show that ALDH enzymes are expressed by both colonic macrophages and dendritic cells. Further, during an on-going T. muris infection, ALDH expression is repressed from uninfected levels and only recovers to normal levels following expulsion of the parasite. These results suggest that local regulation of cellular levels of retinoic acid is an important component of infection-driven inflammation."
"This study evaluates the effects of retinol on intestinal barrier function, growth, total parasites and Giardia spp. infections in children in the Northeast of Brazil." To increase the enrollment of children with marginally low levels of retinol and more prone to malnutrition, only children that had not exclusively been breast-fed were selected.
Children were treated with retinyl palmitate (100,000 IU for children <12 months and 200,000 IU for children at least 12 months old). The placebo group received 40 IU tocopherol. The children received the first supplementation at enrollment, a second dose after 4 months, and a final dose at 8 month.
Conclusions
"These data showed that total parasitic infection and Giardia spp. infections were significantly lower in the vitamin A treatment group when compared to the placebo group, suggesting that vitamin A improves host defenses against Giardia infections."
+++++
The second study examines possible mechanism:
The retinoic acid-producing capacity of gut dendritic cells and macrophages is reduced during persistent T. muris infection.
Abstract
"Trichuris muris is an intestinal nematode that invades the colonic epithelium triggering a mucosal inflammation. Vitamin A and its active metabolite retinoic acid are strongly linked with the modulation of gut immune responses. Here, we describe the temporal changes in the expression of aldehyde dehydrogenase (ALDH) enzymes, responsible for converting dietary-absorbed vitamin A into the immuno-modulatory retinoic acid in lamina propria leucocytes post-infection. We show that ALDH enzymes are expressed by both colonic macrophages and dendritic cells. Further, during an on-going T. muris infection, ALDH expression is repressed from uninfected levels and only recovers to normal levels following expulsion of the parasite. These results suggest that local regulation of cellular levels of retinoic acid is an important component of infection-driven inflammation."
