Features, Causes and Consequences of Splanchnic Sequestration of Amino Acid in Old Rats
Features, Causes and Consequences of Splanchnic Sequestration of Amino Acid in Old Rats
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DOI：
10.1371/journal.pone.0027002
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发表时间：
2011-11-08
期刊：
影响因子：
3.7
通讯作者：
Aussel, Christian
中科院分区：
文献类型：
--
作者：
Jourdan, Marion;Deutz, Nicolaas E. P.;Aussel, Christian
基本原理：在老年受试者中，内脏提取的氨基酸（AA）增加，在一个过程中称为内脏螯合的氨基酸（SSAA）。这一过程可能通过降低饮食AA的外周可用性而导致肌肉质量的年龄相关性进行性下降。SSAA的机制是未知的，但可能涉及增加净利用摄入AA在内脏area.Objectives：使用稳定同位素方法在喂养的成年和老年大鼠提供洞察与年龄相关的SSAA使用三个假设：1）肠道和/或肝脏中蛋白质合成的增加，2）与尿素生成增加相关的AA氧化的增加，3）枯否细胞（KC）激活，导致年龄相关的低度炎症反应。结果：老年大鼠内脏提取亮氨酸（SPELeu）较成年大鼠增加一倍，KC失活后无变化。肠道和肝脏蛋白质合成没有年龄相关的影响，但尿素合成在老年大鼠较低，并与肝脏精氨酸利用率呈负相关。净全身蛋白质合成和动脉AA水平较低，老年大鼠和SPELeu.Conclusion负相关：SSAA是不是年龄相关的尿素生成，肠道或肝脏蛋白质合成或KC活性的改变的后果。然而，SSAA可能与净全身蛋白质合成减少有关，因此与衰老期间发生的瘦体重减少有关。
Rationale: In elderly subjects, splanchnic extraction of amino acids (AA) increases during meals in a process known as splanchnic sequestration of amino acids (SSAA). This process potentially contributes to the age-related progressive decline in muscle mass via reduced peripheral availability of dietary AA. SSAA mechanisms are unknown but may involve an increased net utilization of ingested AA in the splanchnic area.Objectives: Using stable isotope methodology in fed adult and old rats to provide insight into age-related SSAA using three hypotheses: 1) an increase in protein synthesis in the gut and/or the liver, 2) an increase in AA oxidation related to an increased ureagenesis, and 3) Kupffer cell (KC) activation consequently to age-related low-grade inflammation.Findings: Splanchnic extraction of Leu (SPELeu) was doubled in old rats compared to adult rats and was not changed after KC inactivation. No age-related effects on gut and liver protein synthesis were observed, but urea synthesis was lower in old rats and negatively correlated to liver Arg utilization. Net whole-body protein synthesis and arterial AA levels were lower in old rats and correlated negatively with SPELeu.Conclusion: SSAA is not the consequence of age-related alterations in ureagenesis, gut or liver protein synthesis or of KC activity. However, SSAA may be related to reduced net whole-body protein synthesis and consequently to the reduced lean body mass that occurs during aging.