| 1. |
- Calder, Philip C, et al.
(författare)
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Early nutrition and immunity - progress and perspectives.
- 2006
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Ingår i: The British journal of nutrition. - 0007-1145. ; 96:4, s. 774-90
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Forskningsöversikt (refereegranskat)abstract
- The immune system exists to protect the host against pathogenic organisms and highly complex pathways of recognition, response, elimination and memory have evolved in order to fulfil this role. The immune system also acts to ensure tolerance to 'self', to food and other environmental components, and to commensal bacteria. A breakdown in the tolerogenic pathways can also lead to inflammatory diseases. The prevalence of inflammatory diseases, including atopic disorders, has increased over the last 60 years. The development of tolerance is the result of active immune mechanisms and both development and maintenance of tolerance are lifelong processes which start very early in life, even prenatally. Profound immunologic changes occur during pregnancy, involving a polarization of T helper (Th) cells towards a dominance of Th2 and regulatory T cell effector responses in both mother and fetus. This situation is important to maintain pregnancy through avoidance of the rejection of the immunologically incompatible fetus. During the third trimester of human pregnancy, fetal T cells are able to mount antigen-specific responses to environmental and food-derived antigens and antigen-specific T cells are detectable in cord blood in virtually all newborns indicating in utero sensitization. If the neonatal immune system is not able to down-regulate the pre-existing Th2 dominance effectively then an allergic phenotype may develop. Changes occur at, and soon after, birth in order that the immune system of the neonate becomes competent and functional and that the gut becomes colonized with bacteria. Exposure to bacteria during birth and from the mother's skin and the provision of immunologic factors in breast milk are amongst the key events that promote maturation of the infant's gut and gut-associated and systemic immune systems. The introduction of formula and of solid foods exposes the infant to novel food antigens and also affects the gut flora. Nutrition may be the source of antigens to which the immune system must become tolerant, provide factors, including nutrients, that themselves might modulate immune maturation and responses, and provide factors that influence intestinal flora, which in turn will affect antigen exposure, immune maturation and immune responses. Through these mechanisms it is possible that nutrition early in life might affect later immune competence, the ability to mount an appropriate immune response upon infection, the ability to develop a tolerogenic response to 'self' and to benign environmental antigens, and the development of immunologic disorders. A Workshop held in February 2006 considered recent findings in the areas of oral tolerance, routes of sensitization to allergens and factors affecting the development of atopic disease; factors influencing the maturation of dendritic cells and the development of regulatory T cells; the influence of gut microflora on immunity, allergic sensitization and infectious disease; the role of nutrition in preventing necrotizing enterocolitis in an animal model of preterm birth; and the role of PUFA of different classes in influencing immune responses and in shaping the development of atopic disease. This report summarizes the content of the lectures and the subsequent discussions.
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| 2. |
- Christiansen, Line I., et al.
(författare)
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Insulin-Like Growth Factor-1 Supplementation Promotes Brain Maturation in Preterm Pigs
- 2023
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Ingår i: eNeuro. - 2373-2822. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Very preterm infants show low levels of insulin-like growth factor-1 (IGF-1), which is associated with postnatal growth restriction and poor neurologic outcomes. It remains unknown whether supplemental IGF-1 may stimulate neurode-velopment in preterm neonates. Using cesarean-delivered preterm pigs as a model of preterm infants, we investi-gated the effects of supplemental IGF-1 on motor function and on regional and cellular brain development. Pigs were treated with 2.25 mg/kg/d recombinant human IGF-1/IGF binding protein-3 complex from birth until day 5 or 9 before the collection of brain samples for quantitative immunohistochemistry (IHC), RNA sequencing, and quantitative PCR analyses. Brain protein synthesis was measured using in vivo labeling with [2H5] phenylalanine. We showed that the IGF-1 receptor was widely distributed in the brain and largely coexisted with immature neurons. Region-spe-cific quantification of IHC labeling showed that IGF-1 treatment promoted neuronal differentiation, increased subcorti-cal myelination, and attenuated synaptogenesis in a region-dependent and time-dependent manner. The expression levels of genes involved in neuronal and oligodendrocyte maturation, and angiogenic and transport functions were al-tered, reflecting enhanced brain maturation in response to IGF-1 treatment. Cerebellar protein synthesis was increased by 19% at day 5 and 14% at day 9 after IGF-1 treatment. Treatment had no effect on Iba1+ microglia or regional brain weights and did not affect motor development or the expression of genes related to IGF-1 signaling. In conclusion, the data show that supplemental IGF-1 promotes brain maturation in newborn preterm pigs. The results provide further support for IGF-1 supplementation therapy in the early postnatal period in preterm infants.
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| 3. |
- Everaert, Nadia, et al.
(författare)
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A review on early gut maturation and colonization in pigs, including biological and dietary factors affecting gut homeostasis
- 2017
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Ingår i: Animal Feed Science and Technology. - : Elsevier BV. - 0377-8401. ; 233, s. 89-103
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Tidskriftsartikel (refereegranskat)abstract
- During the prenatal, neonatal and post-weaning periods, the mammalian gastrointestinal tract undergoes various morphological and physiological changes alongside with an expansion of the immune system and microbial ecosystem. This review focuses on the time period before weaning and summarizes the current knowledge regarding i) structural and functional aspects ii) the development of the immune system, and iii) the establishment of the gut ecosystem of the porcine intestine. Structural and functional maturation of the gastrointestinal tract gradually progress with age. In the neonatal period colostrum induces gut closure, leads to an increase in intestinal weight, absorptive area and brush border enzyme activities. During the first weeks of life, an increased secretion of stomach and pancreatic enzymes and an increased uptake of monosaccharides and amino acids are observed. The development in digestive function coincides with development in both the adaptive and innate immune system. This secures a balanced immune response to the ingested milk-derived macromolecules, and colonizing bacteria. Husbandry and dietary interventions in early life appear to affect the development of multiple components of the mucosal immune system. Furthermore, the composition of the intestinal microbial communities seems to be affected by the early postnatal environment, which might also contribute to gut maturation, metabolic and immune development. Understanding the interplay between morphological, functional and immunological maturation, as influenced by early microbial colonization and ingestion of dietary factors, is of utmost importance to identify management and feeding strategies to optimize intestinal health. We discuss some possible implications related to intrauterine growth restriction, and preterm delivery as these both dramatically increase the risk of mortality and morbidity. In addition, some nutritional interventions during the perinatal period in both sows and piglets will be discussed in the light of possible health consequences early in life and later on.
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| 4. |
- Kang, Wenjing, et al.
(författare)
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Survey of 800+data sets from human tissue and body fluid reveals xenomiRs are likely artifacts
- 2017
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Ingår i: RNA. - : Cold Spring Harbor Laboratory. - 1355-8382 .- 1469-9001. ; 23:4, s. 433-445
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Tidskriftsartikel (refereegranskat)abstract
- miRNAs are small 22-nucleotide RNAs that can post-transcriptionally regulate gene expression. It has been proposed that dietary plant miRNAs can enter the human bloodstream and regulate host transcripts; however, these findings have been widely disputed. We here conduct the first comprehensive meta-study in the field, surveying the presence and abundances of cross-species miRNAs (xenomiRs) in 824 sequencing data sets from various human tissues and body fluids. We find that xenomiRs are commonly present in tissues (17%) and body fluids (69%); however, the abundances are low, comprising 0.001% of host human miRNA counts. Further, we do not detect a significant enrichment of xenomiRs in sequencing data originating from tissues and body fluids that are exposed to dietary intake (such as liver). Likewise, there is no significant depletion of xenomiRs in tissues and body fluids that are relatively separated from the main bloodstream (such as brain and cerebro-spinal fluids). Interestingly, the majority (81%) of body fluid xenomiRs stem from rodents, which are a rare human dietary contribution but common laboratory animals. Body fluid samples from the same studies tend to group together when clustered by xenomiR compositions, suggesting technical batch effects. Last, we performed carefully designed and controlled animal feeding studies, in which we detected no transfer of plant miRNAs into rat blood, or bovine milk sequences into piglet blood. In summary, our comprehensive computational and experimental results indicate that xenomiRs originate from technical artifacts rather than dietary intake.
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