Protein and amino acid metabolism in malnutrition and metabolic stress

营养不良与感染的协同作用是一个复杂的多因素问题，在世界范围内具有破坏性影响。炎症和免疫系统的激活，都是对组织损伤和感染的正常反应，导致1)谷胱甘肽（GSH）合成增加，以平衡自由基产生的增加；2)急性期蛋白质合成增加。这两种反应都增加了对可能不足的氨基酸供应的需求。在营养不良期间，这些反应可能进一步损害生长，并可能损害自身。我们新的稳定同位素技术测量组织蛋白质合成以及谷胱甘肽和个体血浆蛋白的合成，可以全面检查个体蛋白质或氨基酸产物在营养不良和/或氧化应激状态下如何维持，增加或耗尽的机制。

The synergistic interaction of malnutrition with infections is a complex multifactorial problem with devastating impact worldwide. Inflammation and activation of the immune system, which are both normal responses to tissue injury and infection, result in 1) increased synthesis of glutathione (GSH) to balance the increased production of free radicals and 2) increased synthesis of acute phase proteins. Both responses result in increased demands for a potentially meagre supply of amino acids. During malnutrition these responses may further compromise growth and may be compromised themselves. Our new stable isotope techniques to measure tissue protein synthesis as well as synthesis of GSH and individual plasma proteins allow comprehensive examination of the mechanisms of how pools of individual proteins or products of amino acids are maintained, augmented or depleted in states of malnutrition and/or oxidative stress.