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[Innovation in the incorporation of macronutrients to enteral nutrition formulas].
Gil Hernández, Á
Nutricion hospitalaria. 2018;(Spec no2):4-12
Abstract
Enteral nutrition consists of the administration of chemically defined nutrients which are partially or fully metabolised in the intestinal tract, by the oral route or through a tube, to get an adequate and efficient nutritional supply. Enteral nutrition is the first option when one needs artificial nutrition, keeping parenteral nutrition only for those cases for which enteral nutrition would be insufficient or impossible. Enteral nutrition formulas are classified according to their composition with complete or uncompleted supply of nutrients, administration route, and protein content, energy density and type and content of fibre, and in second term according to general or special purposes utilization. Indeed, enteral nutrition formulas can be grouped as polymeric, oligomeric, organ-specific, therapeutic formulas, and nutrition supplements and modules. All these formulas are susceptible of improvement and innovation based mainly on the knowledge of diseases physiopathology, composition and functionality of food ingredients, which in turn contain a number of specific nutrients and bioactive compounds able to exert particular effects on the patient, and on technological treatment technology that will result in the amelioration of nutrient bioavailability. The present work reviews some of the most relevant functional ingredients used today in the innovation of enteral formulas, as well as their main physiological and biochemical effects in selected pathologies.
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Candidate genes linking maternal nutrient exposure to offspring health via DNA methylation: a review of existing evidence in humans with specific focus on one-carbon metabolism.
James, P, Sajjadi, S, Tomar, AS, Saffari, A, Fall, CHD, Prentice, AM, Shrestha, S, Issarapu, P, Yadav, DK, Kaur, L, et al
International journal of epidemiology. 2018;(6):1910-1937
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Abstract
BACKGROUND Mounting evidence suggests that nutritional exposures during pregnancy influence the fetal epigenome, and that these epigenetic changes can persist postnatally, with implications for disease risk across the life course. METHODS We review human intergenerational studies using a three-part search strategy. Search 1 investigates associations between preconceptional or pregnancy nutritional exposures, focusing on one-carbon metabolism, and offspring DNA methylation. Search 2 considers associations between offspring DNA methylation at genes found in the first search and growth-related, cardiometabolic and cognitive outcomes. Search 3 isolates those studies explicitly linking maternal nutritional exposure to offspring phenotype via DNA methylation. Finally, we compile all candidate genes and regions of interest identified in the searches and describe their genomic locations, annotations and coverage on the Illumina Infinium Methylation beadchip arrays. RESULTS We summarize findings from the 34 studies found in the first search, the 31 studies found in the second search and the eight studies found in the third search. We provide details of all regions of interest within 45 genes captured by this review. CONCLUSIONS Many studies have investigated imprinted genes as priority loci, but with the adoption of microarray-based platforms other candidate genes and gene classes are now emerging. Despite a wealth of information, the current literature is characterized by heterogeneous exposures and outcomes, and mostly comprise observational associations that are frequently underpowered. The synthesis of current knowledge provided by this review identifies research needs on the pathway to developing possible early life interventions to optimize lifelong health.
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Metabolic flux analysis in Ashbya gossypii using 13C-labeled yeast extract: industrial riboflavin production under complex nutrient conditions.
Schwechheimer, SK, Becker, J, Peyriga, L, Portais, JC, Wittmann, C
Microbial cell factories. 2018;(1):162
Abstract
BACKGROUND The fungus Ashbya gossypii is an important industrial producer of the vitamin riboflavin. Using this microbe, riboflavin is manufactured in a two-stage process based on a rich medium with vegetable oil, yeast extract and different precursors: an initial growth and a subsequent riboflavin production phase. So far, our knowledge on the intracellular metabolic fluxes of the fungus in this complex process is limited, but appears highly relevant to better understand and rationally engineer the underlying metabolism. To quantify intracellular fluxes of growing and riboflavin producing A. gossypii, studies with different 13C tracers were embedded into a framework of experimental design, isotopic labeling analysis by MS and NMR techniques, and model-based data processing. The studies included the use 13C of yeast extract, a key component used in the process. RESULTS During growth, the TCA cycle was found highly active, whereas the cells exhibited a low flux through gluconeogenesis as well as pentose phosphate pathway. Yeast extract was the main carbon donor for anabolism, while vegetable oil selectively contributed to the proteinogenic amino acids glutamate, aspartate, and alanine. During the subsequent riboflavin biosynthetic phase, the carbon flux through the TCA cycle remained high. Regarding riboflavin formation, most of the vitamin's carbon originated from rapeseed oil (81 ± 1%), however extracellular glycine and yeast extract also contributed with 9 ± 0% and 8 ± 0%, respectively. In addition, advanced yeast extract-based building blocks such as guanine and GTP were directly incorporated into the vitamin. CONCLUSION Intracellular carbon fluxes for growth and riboflavin production on vegetable oil provide the first flux insight into a fungus on complex industrial medium. The knowledge gained therefrom is valuable for further strain and process improvement. Yeast extract, while being the main carbon source during growth, contributes valuable building blocks to the synthesis of vitamin B2. This highlights the importance of careful selection of the right yeast extract for a process based on its unique composition.
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Feeding the Walls: How Does Nutrient Availability Regulate Cell Wall Composition?
Ogden, M, Hoefgen, R, Roessner, U, Persson, S, Khan, GA
International journal of molecular sciences. 2018;(9)
Abstract
Nutrients are critical for plants to grow and develop, and nutrient depletion severely affects crop yield. In order to optimize nutrient acquisition, plants adapt their growth and root architecture. Changes in growth are determined by modifications in the cell walls surrounding every plant cell. The plant cell wall, which is largely composed of complex polysaccharides, is essential for plants to attain their shape and to protect cells against the environment. Within the cell wall, cellulose strands form microfibrils that act as a framework for other wall components, including hemicelluloses, pectins, proteins, and, in some cases, callose, lignin, and suberin. Cell wall composition varies, depending on cell and tissue type. It is governed by synthesis, deposition and remodeling of wall components, and determines the physical and structural properties of the cell wall. How nutrient status affects cell wall synthesis and organization, and thus plant growth and morphology, remains poorly understood. In this review, we aim to summarize and synthesize research on the adaptation of root cell walls in response to nutrient availability and the potential role of cell walls in nutrient sensing.
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Is maternal microbial metabolism an early-life determinant of health?
Romano, KA, Rey, FE
Lab animal. 2018;(9):239-243
Abstract
Mounting evidence suggests that environmental stress experienced in utero (for example, maternal nutritional deficits) establishes a predisposition in the newborn to the development of chronic diseases later in life. This concept is often referred to as the "fetal origins hypothesis" or "developmental origins of health and disease". Since its first proposal, epigenetics has emerged as an underlying mechanism explaining how environmental cues become gestationally "encoded". Many of the enzymes that impart and maintain epigenetic modifications are highly sensitive to nutrient availability, which can be influenced by the metabolic activities of the intestinal microbiota. Therefore, the maternal microbiome has the potential to influence epigenetics in utero and modulate offspring's long-term health trajectories. Here we summarize the current understanding of the interactions that occur between the maternal gut microbiome and the essential nutrient choline, that is not only required for fetal development and epigenetic regulation but is also a growth substrate for some microbes. Bacteria able to metabolize choline benefit from the presence of this nutrient and compete with the host for its access, which under extreme conditions may elicit signatures of choline deficiency. Another consequence of bacterial choline metabolism is the accumulation of the pro-inflammatory, pro-thrombotic metabolite trimethylamine-N-oxide (TMAO). Finally, we discuss how these different facets of microbial choline metabolism may influence infant development and health trajectories via epigenetic mechanisms and more broadly place a call to action to better understand how maternal microbial metabolism can shape their offspring's propensity to chronic disease development later in life.
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Human milk composition and infant growth.
Eriksen, KG, Christensen, SH, Lind, MV, Michaelsen, KF
Current opinion in clinical nutrition and metabolic care. 2018;(3):200-206
Abstract
PURPOSE OF REVIEW This review highlights relevant studies published between 2015 and 2017 on human milk composition and the association with infant growth. RECENT FINDINGS High-quality studies investigating how human milk composition is related to infant growth are sparse. Recent observational studies show that human milk concentrations of protein, fat, and carbohydrate likely have important influence on infant growth and body composition. Furthermore, some observational studies examining human milk oligosaccharides and hormone concentrations suggest functional relevance to infant growth. For human milk micronutrient concentrations and microbiota content, and other bioactive components in human milk, the association with infant growth is still speculative and needs further investigation. The included studies in this review are all limited in their methodological design and methods but have interesting potential in understanding infant growth. SUMMARY Available evidence on human milk composition in relation to infant growth is sparse. This review summarizes recent publications investigating human milk composition; including micro- and macronutrients, human milk oligosaccharides, hormones and other bioactive components, and the association with infant weight, length, body mass index, and body composition.
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Unconventional protein secretion triggered by nutrient starvation.
Cruz-Garcia, D, Malhotra, V, Curwin, AJ
Seminars in cell & developmental biology. 2018;:22-28
Abstract
It is usually assumed that eukaryotic cells secrete only proteins that contain a signal sequence for Sec61 mediated translocation into the lumen of endoplasmic reticulum (ER). Surprisingly however, many proteins, such as superoxide dismutase (SOD)1, acyl-CoA binding protein (Acb1), interleukin 1β, fibroblast growth factor 2 and the adipokine Unpaired2, to name a few, are secreted even though they lack a signal sequence. The discovery that these proteins are secreted has presented a new challenge and we describe here a common pathway by which SOD1 and Acb1 are specifically secreted upon nutrient starvation. Their secretion follows a type III unconventional pathway, requiring the exposure of a di-acidic motif, which we propose promotes their capture into a membrane compartment called CUPS (compartment for unconventional protein secretion). We suggest that CUPS, composed of membranes derived from the Golgi apparatus and endosomes, serves as a major sorting station prior to release of SOD1 and Acb1 into the extracellular space. The trafficking of these signal sequence lacking proteins therefore has functional similarities to conventional protein secretion in that they rely on membrane bounded compartments for their sorting and transport, but bypass the need of Sec61 for translocating into the ER and COPII and COPI for their intracellular transfers. This review is part of a Special Issue of SCDB on "unconventional protein secretion" edited by Walter Nickel and Catherine Rabouille.
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Effectiveness of macronutrient supplementation on nutritional status and HIV/AIDS progression: A systematic review and meta-analysis.
Hong, H, Budhathoki, C, Farley, JE
Clinical nutrition ESPEN. 2018;:66-74
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Abstract
BACKGROUND & AIMS Malnutrition is common in Sub-Saharan Africa, weakening the immune function of persons living with HIV infection (PLWH). Being malnourished at the initiation of antiretroviral therapy (ART) leads to higher risk of early mortality and reduced quality of life. Thus, introduction of protein-energy-fortified macronutrient supplements at ART initiation may improve HIV treatment outcomes. This review aimed to evaluate the effectiveness of macronutrient interventions. METHODS This systematic review and meta-analysis included 15 studies conducted from 2000 to 2015 among Sub-Saharan African adults. RESULTS Six randomized controlled trials and 4 retrospective cohort studies provided data eligible for a meta-analysis. Supplementation significantly increased the overall standardized mean difference (SMD) between baseline and follow-up data in weight (SMD = 0.382, p < .001), BMI (SMD = 0.799, p < .001); fat-free mass (SMD = 0.154, p = .009); and CD4 count (SMD = 0.428, p < .001). CONCLUSION Protein-energy-fortified macronutrient supplementation at ART initiation may positively influence nutritional status and immunologic response in PLWH in Sub-Saharan Africa.
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An Optimized Rhizobox Protocol to Visualize Root Growth and Responsiveness to Localized Nutrients.
Schmidt, JE, Lowry, C, Gaudin, ACM
Journal of visualized experiments : JoVE. 2018;(140)
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Abstract
Roots are notoriously difficult to study. Soil is both a visual and mechanical barrier, making it difficult to track roots in situ without destructive harvest or expensive equipment. We present a customizable and affordable rhizobox method that allows the non-destructive visualization of root growth over time and is particularly well-suited to studying root plasticity in response to localized resource patches. The method was validated by assessing maize genotypic variation in plasticity responses to patches containing 15N-labeled legume residue. Methods are described to obtain representative developmental measurements over time, measure root length density in resource-containing and control patches, calculate root growth rates, and determine 15N recovery by plant roots and shoots. Advantages, caveats, and potential future applications of the method are also discussed. Although care must be taken to ensure that experimental conditions do not bias root growth data, the rhizobox protocol presented here yields reliable results if carried out with sufficient attention to detail.
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Amino acid transporter SLC7A11/xCT at the crossroads of regulating redox homeostasis and nutrient dependency of cancer.
Koppula, P, Zhang, Y, Zhuang, L, Gan, B
Cancer communications (London, England). 2018;(1):12
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Abstract
Cancer cells often upregulate nutrient transporters to fulfill their increased biosynthetic and bioenergetic needs, and to maintain redox homeostasis. One nutrient transporter frequently overexpressed in human cancers is the cystine/glutamate antiporter solute carrier family 7 member 11 (SLC7A11; also known as xCT). SLC7A11 promotes cystine uptake and glutathione biosynthesis, resulting in protection from oxidative stress and ferroptotic cell death. Recent studies have unexpectedly revealed that SLC7A11 also plays critical roles in glutamine metabolism and regulates the glucose and glutamine dependency of cancer cells. This review discusses the roles of SLC7A11 in regulating the antioxidant response and nutrient dependency of cancer cells, explores our current understanding of SLC7A11 regulation in cancer metabolism, and highlights key open questions for future studies in this emerging research area. A deeper understanding of SLC7A11 in cancer metabolism may identify new therapeutic opportunities to target this important amino acid transporter for cancer treatment.